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DEER

Content Updated: 27th August 2013

CONTENTS:

Taxonomy
Evolution
Sexing
Antler Development (Summary)
Food and Feeding
Senses
  -- Vision
  -- Olfaction (Smell)
  -- Audiology (Hearing)
Behaviour and Sociality
Interaction with Humans
  -- Hunting and Deer Parks
  -- Damage to Agriculture
  -- Decline in Plant and Bird Species
  -- Damage to People, Property and Pets
  -- Traffic Collisions
  -- Art and Culture Subject
  -- Feeding Interactions
Internal Links and Q/As

The following is a brief overview of some of the easily generalised aspects of deer natural history – for species-specific information, the reader is directed to the links below and at the bottom of the page.  This part of the site is still a work in progress and many of the articles are in preparation – links will be activated as the new content comes online and until the full profiles are up, the species links will redirect you to the Speed Read profiles.

There are nine species of deer living in the UK: Red (Cervus elaphus); Fallow (Dama dama); Roe (Capreolus capreolus), Sika (Cervus nippon); Muntjac (Muntiacus reevesi); Reindeer (Rangifer tarandus); Chinese Water (Hydropotes inermis); Chital (Axis axis); and Pere David's deer (Elaphurus davidianus). Six of these are found wild, and three (Reindeer, Chital and Pere David's) are found exclusively in parks.

Taxonomy: There is an expression that goes something along the lines of ‘nothing that is worth doing is ever easy’. While I can think of a few things to which that idea doesn’t apply, it certainly seems applicable to the task of classifying mammals. In Linnaeus’ time, the situation was a little more straightforward, with animal groups assembled primarily on the way the critters looked. With the advent of molecular genetics, it has become increasingly apparent that morphology may not always provide the best taxonomic identifiers. Thus, we find ourselves in a situation where different techniques for measuring and weighting taxonomic characters led to the different arrangement of species. Much has happened to the arrangement of the mammals in the last half-century and there are many groups -- of which deer are one -- for which the relationships are still not fully resolved. That which follows is a summary of the situation to date; readers interested in more details of how we classify organisms are directed to the Taxonomy page.

So, let’s start with what we can say with any degree of certainty.  All of the critters that we know as mammals are grouped together within the class Mammalia; within this class sits an infraclass (infra being Latin for “below”) called the Eutheria (or "true beasts"), which contains all the placental mammals (that is, all mammals except monotremes like the platypus and marsupials like the kangaroos). It is reasonably well established that the Eutheria can be broadly divided into four superorders: the Euarchontoglires (primates, rodents, hares and rabbits); the Xenarthra (anteaters and armadillos); the Afrotheria (elephants and manatees); and, of interest to us here, the Laurasiatheria, which holds the deer (along with various other critters including cows, bats and all the carnivores).

Killer WhaleThe first major sticking point we encounter now is on the placement of the order Cetacea (the whales and dolphins). Molecular data strongly supports the view of renowned mammalogist Sir William Flower who, in 1891 proposed -- based on similarities in the larynx and several internal organs -- that the cetaceans should be grouped with the deer (and other related mammals) currently placed in the Artiodactyla order; this would form an, as yet unranked, group called the Cetartiodactyla.  Despite the molecular data, there is debate among taxonomists as to whether this grouping is a valid taxonomic clade. It seems that while most morphological taxonomists generally support the idea of a clade uniting the two orders, some disagree that the Cetacea evolved from within the Artiodactyla; instead, they prefer to consider the Cetacea and Artiodactyla sister groups (i.e. they’re more closely related to each other than to any other order). To my mind, the current evidence seems pretty convincing and I suspect further study will validate the grouping. However, given the currently tenuous status of Cetaritodactyla as a clade in its own right, I have opted to follow a more ‘mainstream’ scheme here.

By this point, you might be wondering what happened to deer being ungulates (i.e. hoofed animals) – whatever happened to this as a taxonomic unit? Well, back in 1766, Carl von Linne did indeed group all hoofed mammals under the umbrella (more specifically known as a grandorder) Ungulata, stemming from the Latin unguis, meaning “nail” or “hoof”. Of late, however, there has been much debate over the validity of Ungulata as a taxonomic clade; as recently as 2004 Andrew Duff and Ann Lawson included the Ungulata as a grandorder in their checklist of mammals of the world. Nonetheless, the current consensus is that the ungulates don’t represent a genetic unit; that is to say that they’re not a group of mammals more closely related to one another than to other (non-ungulate) mammals. Rather, it seems that the ungulates form an evolutionary grade – in other words, they’re a group whose members have evolved similar adaptations (significantly, although not limited to, hooves in place of claws). Indeed, ungulates have evolved to walk on what are effectively their tiptoes and this condition is referred to as an unguligrade gait. So, in essence, the ungulates still exist as a biological group, but just not as a taxonomic one (much like the insectivores, which are a valid feeding guild, but the Insectivora is no longer a valid taxon).

As it currently stands, the Laurasiatheria superorder holds eight orders and the ungulates are split -- unevenly -- between two of them: the Artiodactyla and Perissodactyla.

The Perissodactyla -- from the Greek perissos, meaning “odd” or “uneven” and daktulos, meaning “finger” or “toe” -- comprises those mammals with what anatomists call a “mesaxonic” limb structure; in other words, they walk on the equivalent of the tip of either a single digit or the tips of three digits, depending on the species (by “digit”, I mean finger/toe). This order contains three families, six genera and about 15 species, including horses, zebras, rhinoceroses and tapirs.  Perissodactylian taxonomy is fascinating in its own right -- especially a molecular study published in 2006, which suggested that the perissodactylians should be grouped with the bats, carnivores and pangolins in the superorder Pegasoferae -- but it is not directly relevant to us here and I won’t pursue it further.

Diagram of deer hoof

The Artiodactyla -- from the Greek artios, meaning “even” -- contains mammals with a “paraxonic” limb structure; that is, they walk on the third and fourth digits, which are surrounded by keratinizaed hooves.  Digits two and five have been reduced to near vestigial status higher up the foot, called “dew claws” (see red arrows in graphic above). In the case of deer, and most other ruminants (which we’ll come to in a moment), the third and fourth metapodials -- these are the bones in the foot between the ankle and toes -- are fused, which makes it seem as though the two toes emerge from the end of a single bone and produces the familiar “cloven-hoofed” appearance. The order holds ten families, between 79 and 81 genera (depending on the classification one prefers) and around 230 species, including pigs, peccaries, hippopotamuses, camels, giraffes, sheep, cows and, of course, deer.

LlamasThe Artiodactyla can be further divided into four suborders; the one we’re interested in is the Ruminatia. It should be mentioned that although all animals within the Ruminatia suborder are ruminants (i.e.  they ferment plant matter in their stomachs to aid digestion), not all ruminants are members of the Ruminatia – llamas and camels, for example, are artiodactyls that ruminate but are part of the Tylopoda suborder rather than the Ruminatia. The Ruminatia can be split into two groups (or infraorders): the Tragulina (the “lower ruminants”, containing only the chevrotain, or mouse deer) and the Pecora (“higher ruminants”, containing the ‘horned’ species). Within the Pecora sits -- among various other families, including that containing the giraffes and okapis -- the Cervidae (the deer family), which contains 16 genera and some 51 species. Incidentally, in his Natural History of British Mammals, Derek Yalden suggests that deor was probably the precursor for the modern word “deer”, originally it simply meant “beast” and so could be used in reference to any animal.

In a 46 page contribution to the Proceedings of the Zoological Society of London during 1878, 19th Century sportsman and naturalist Sir Victor Brooke suggested that the Cervidae could be broadly split into two groups (here we go again!), based on the structure of the bones in their feet. In order to understand this division, we need to take a moment to consider the anatomy of mammalian hands and feet. Your hand is composed of 27 bones (there are 28 in your foot) grouped into three sets. By curling your hand, you can see that your fingers have three sections; these are collectively termed the phalanges (or finger bones); the same name is given to those making up the toes. Attached to the phalanges (at the “major” knuckle) are five -- one for each finger (or toe) -- longer bones called metacarpals (in the foot they’re called metapodials), which in turn are connected to a group of smaller bones making up your carpus, or wrist (in the foot, the bones of the heel and ankle are collectively termed the tarsus). It is the metacarpals that are of interest to us here and it is worth noting that anatomists number them from one to five, starting at the thumb or big toe (so the thumb’s metacarpal is number one, while the pinky’s metacarpal is number five).

Brooke split the deer into those that retained only the distil end of the second and fifth metacarpals (i.e. the bits closest to the phalanges/fingers of the index and pinky finger) and those that retained the proximal (carpal/wrist) ends of the same bones; he named them Telemetacarpalian and Plesiometacarpalian deer, respectively. Splitting organisms into groups based on geographic regions was also common practice during the 19th Century (perhaps more so than it is today) and, as such, these deer groupings are also referred to as New World (Telemetacarpalia) and Old World (Plesiometacarpalia) species. If you picture a map of the globe and draw a line from pole-to-pole down the middle of the Atlantic Ocean, everything to the left-hand side (e.g.  Canada, North America, South America etc.) plus Australia and New Zealand is the “New World”, while everything to the right (excluding Australia and New Zealand, of course) is the “Old World”.

Deer feet diagram
Bone arrangement in mammalian limbs. Phalanges in green; Metacarpals in red; Carpus/Tarsus in purple. Second and fifth metacarpals in yellow to emphasise plesiometacarpalian and telemetacarpalian conditions.

At the time of Brooke’s classification, the telemetacarpalian deer (sometimes called Capreoline) included Roe, Chinese water deer, Moose, Black- and White-tailed deer and Reindeer. Plesiometacarpalian (or Cervine) deer, included Red, Sika, Muntjac, Fallow, Axis and Pere David’s deer. There has been some debate as to the validity of these groups as taxonomic units (which we’ll come to in a moment), but most studies have found a split between the deer corresponding roughly to the geographical regions of the Old and New Worlds. Indeed, data from mitochondrial DNA studies suggest that New and Old World deer shared a common ancestor that lived back in the late Miocene, splitting some 9.5 to 12.5 million years ago.

Since their proposition just over 130 years ago, the validity of the Telemetacarpalia and Plesiometacarpalia as taxonomic units has been hotly debated. While there is some geographical and morphological evidence in support of this division, many studies have failed to find support for the Telemetacarpalia; even where support is found, the interrelationships among the species remain unresolved. In their 1987 review of relationships among living deer, for example, Australian Natural University biologist Colin Groves and British-based taxonomist Peter Grubb argued that the lack of antlers in Chinese water deer (Hydropotes spp.) is one of the features suggesting that they formed a sister group to all remaining Cervidae species. If this is indeed the case, the Telemetacarpalia as defined by Brooke isn’t a valid taxon.  Similarly, in a paper to the Proceedings of the Royal Society of London published during 1998, Ettore Randi at the Istituto Nazionale per la Fauna Selvatica in Italy and colleagues presented cytochrome b data for 11 deer species and failed to find any support for the Telemetacarpalia; they also disagreed with Groves and Grubb, suggesting that Hydropotes is actually nestled with the Black- and White-tailed deer, rather than being the sister group of the Cervidae.

The situation seems less controversial for the Plesiometacarpalia, although recent molecular data has thrown up some interesting placements for deer currently ascribed to the Cervus genus; if borne out, they could invalidate the Plesiometacarpalia. The situation can be rather mindboggling to the non-taxonomist, but the general view seems to be that while the Plesiometacarpalin deer are a valid group, Telemetacarpalin deer aren’t. With this in mind, how should the deer be split? Unfortunately, there’s no universally accepted answer to this question, but by using a combination of morphological and molecular data, we can hazard a reasonable guess.

The following scheme is based on the major taxonomic analysis of deer (using mitochondrial and nuclear DNA) published in 2006 by a team of French taxonomists at the Museum National d’Historie Naturelle in Paris, led by Clement Gilbert. In their scheme, Gilbert and his team divided the Cervidae family into two sub-families: the Cervinae, and the Capreolinae. The deer are then divvied up between the sub-families as follows:

Family: Cervidae (Deer)

Sub-Family: Cervinae (Old World Deer)
Tribe: Cervini (True deer)
Genera: Cervus (Red, Sika, Sambar, Elk, etc.), Axis (Chital deer), Dama (Fallow deer) and Rucervus (Swamp deer)

Tribe: Muntiacini (Muntjacs)
Genera: Muntiacus (Muntjacs) and Elaphodus (Tufted deer)

Sub-Family: Capreolinae (New World Deer)
Tribe: Capreolini (New World Deer)
Genera: Capreolus (Roe deer) and Hydropotes (Chinese water deer)

Tribe: Alceini (Moose)
Genus: Alces (Moose)

Tribe: Odocoileini (Mule deer)
Genera: Rangifer (Reindeer), Odocoileus (Black- and White-tailed deer), Blastocerus (Marsh deer), Pudu (Pudu), Hippocamelus (Andean deer), Mazama (Brocket deer) and Ozotoceros (Pampas deer)

The data presented by Gilbert and his colleagues provide interesting phylogenetic fodder: they suggest that the genus Mazama -- currently holding the Brocket deer -- may be invalid (so the Brocket deer would need to be reclassified); they assign the Pere David’s deer from its own genus (Elaphurus) to the Cervus genus; and they move the Barasingha (or Swamp) deer out of the Cervus genus and into its own genus (Rucervus). These amendments don’t concern us here, so I won’t delve any further into this, but it is reasonable to say that the face of deer taxonomy has undergone some considerable changes in recent years and the situation is still not resolved.

Roe buck among buttercups
The phylogenetic placement of the Roe deer (Capreolus capreolus) provides a sticking point in the telemetacarpalain and plesiometacarpalian classification schemes.

A more recent phylogenetic analysis, published during 2008, in the same journal as Gilbert’s study was largely in support of the French biologists’ findings, although they made some slight re-arrangements, including considering the tribes as sub-families. The authors also suggested that, until further clarification (i.e. data) is available, the 2006 Cervidae classification proposed by Gilbert and his team should be adopted. I have followed the 2006 scheme above, to the exclusion of referring to the Cervinae as Plesiometacarpalia and the Capreolinae as Telemetacarpalia (which the 2006 study supported). The data from the 2008 study suggested that the Capreolini and Alceini are more closely related to the Muntiacini and Cervini than to the Odocoileini (which conflicts with the idea of the Telemetacarpalia as a taxon) and I have chosen to follow that here. The 2008 study did find support for Plesiometacarpalia, but I have refrained from using that in the above scheme in a bid to avoid further confusion. Where changes have been made to the grouping of individual genera of deer, I will attempt to provide a summary in the relevant species’ section on this site (this includes a treatment of Cervus classification on the Red deer page).

There are two final points I would like to clarify before moving on.  Firstly, it is worth mentioning that there may be some confusion over the validity of the Odocoilinae as a family. Some sources point out that this family is what’s referred to as an “invalid junior synonym” of Capreolinae. In other words, Capreolinae appeared in the literature before Odocoilinae (in 1828 and 1923, respectively) and early ‘trumps’ recent in taxonomic circles. Some authors, however, still make reference to the latter as a valid family (the 2008 scheme referenced earlier, for example). Basically, the problem revolves around the placement of the genera Capreolus, Alces and Hydroptes. If the aforementioned three genera are included with the remaining American species (i.e.  Odocoileus, Hippocamelus, Mazama, etc.) then the correct name is Capreolinae; if they’re not present, then Odocoilinae is valid.

Secondly, there is another group of deer as distinct from those we’ve already spoken about: they are the Musk deer of the south Asian mountains. These deer appear to be more primitive (in the taxonomic sense) than the Cervidae species, lacking antlers, possessing a gall bladder and a musk gland (the secretion of which is used as a perfume fixative). These seven species are grouped into their own family -- the Moschidae (genus Moschus) -- within the Pecora and are the sister group to the Cervidae/Bovidae, so they’re more closely related to the ‘true’ deer and the cows, goats and sheep etc., than to the giraffes or the pronghorns that are also in this infraorder. Indeed, several authors have pointed out how Musk deer seem to possess both cervid and bovid features. (Back to Menu)

MuntjacEvolution: In her 2003 booklet, Understanding Deer, Jeanette Lawton writes that the first ungulates appear in the fossil record about 50 million years ago (mya), during the Eocene. These animals subsequently evolved into two groups: those with an even number of toes (the Artiodactyls) and those with an uneven number of toes (the Perissodactyls). Ms Lawton points out that the first deer didn’t appear on the scene until about 25 mya after these early ungulates. Indeed, the animals that many consider to be the precursors to deer -- animals such as Syndyoceras, which seems to share features with deer, horses, giraffes and antelopes -- had bony skull outgrowths similar to non-deciduous antlers and were found in North America some 35 million years ago (mya), during the Miocene. Remains of one of the world’s oldest known antler-shedding deer, Dicrocerus elegans, are found in European sediment deposits dating back to between 15 and 30 mya; these were small deer, similar to the muntjacs we see today (see right), and it has been suggested that the modern muntjacs and tufted deer are probably descended from these. Modern ‘true’ deer are thought to have evolved from ancestors similar to modern-day chevrotains at some point during the Oligocene (part of the mid-Tertiary, some 30 mya); they were small animals with simple antlers and large canine tusks that lived in the forests of the Old World tropics.

In his Deer of the World, Canada-based deer biologist Valerius Geist points out that deer thrive in environmental turmoil – in his book, Geist writes: “Such turmoil became increasingly frequent as minor glaciations punctuated the warm Tertiary period and escalated to the major glaciations of the Pleistocene or Ice Age.” In his contribution to the Encyclopedia of Mammals, Geist describes how the early Pliocene of Eurasia (about 5 mya) saw increasingly larger glaciations; large glaciers pulverise rock to produce mineral-rich dust that is distributed by water and wind to form highly fertile soils. Dr Geist explains: “Large-antlered deer thus appeared repeatedly, beginning with the minor glaciations late in the Pliocene and continuing into the major glaciations of the Pleistocene from about 1.8 million years ago”.

Precise dates for the deer appearances and radiations are difficult to be sure of and molecular data often conflict with fossil evidence.  Nonetheless, it appears that much of the deer radiation has occurred since the end of the Miocene. Fossil and molecular data suggest that the Cervinae split from the Muntiacinae about 7 mya. The muntjacs have persevered almost unchanged since this split, while the cervine deer have diversified considerably (much of which seems to have occurred in the last 2 mya). In their 1998 paper to the Proceedings of the Royal Society of London, Ettore Randi and his colleagues suggest that Axis, Dama and Cervus originated during the Upper Miocene, while the main evolutionary lineages among the Cervus species arose and diverged in the Pliocene. In a 2004 paper to the journal Molecular Phylogenetics and Evolution, Christian Pitra and three colleagues present a cladogram -- largely supporting the conclusions of Randi and his colleagues -- suggesting that both Axis and Dama arose during the mid-Pliocene, around 5 mya. These data tie in quite nicely with the fossil data we currently have. The first fossils of Cervus appear at the Miocene-Pliocene boundary, between 4.3 and 6.8 mya.

European species were able to colonise the British Isles when the North Sea virtually dried up during the last Ice Age. Deer thrived in the UK during the various Interglacial periods and there is considerable fossil evidence to suggest that the dense forests of the Stone Age were home to large Red deer. When the ice retreated some 8,000 to 10,000 years ago, the land bridge was closed and the deer were cut off from the rest of Europe. Since then the ecological turmoil, in which they do so well, has been provided by humans.

For a fascinating and detailed account of deer evolution, the reader is directed to Deer of the World: Their Evolution, Behavior and Ecology, by Valerius Geist. (Back to Menu)

Sexing: Adult males (stags or bucks - see table below) of all five species of deer referred to here are easily separated from adult females (does or hinds - see table) during the breeding (rutting) season by the presence of antlers. From birth, the pedicles from which antlers will grow begin to develop in males and from about 10 months old appendages easily identifiable as antlers can be seen. There are cases where females develop antlers (e.g. in older Roe does) -- but these tend to be rather small and unbranched -- and where males fail to develop antlers (these are called “hummels” or “Notts”, varying geographically).  Additionally, the males of some species (e.g. Red and Fallow) develop prominent prominentia laryngea (Adam’s apple) and manes during the breeding season. Males also exhibit a hair-covered penis sheath. Males of all five species are typically larger and heavier than females, although this can be difficult to assess without some basis for comparison. In some species there are additional features that can be used to sex an individual – in Roe, for example, does have a tuft of hair at the base of the rump that is absent in bucks. The sexes of most species spend much of the year apart, coming together during the breeding season. (Back to Menu)

Fallow penis sheath
Penis sheath of Fallow buck.

Names of male and female deer table

Antler Development (Summary): Unlike horns, which are permanent structures, antlers are shed and re-grown each year. Some deer begin growing their new antlers almost immediately after the old ones have been shed, while other species exhibit a delay between shedding and re-growth.

Horns consist of a bony projection of the frontal (forehead) bone enclosed by a sleeve of keratin – they maintain a venous (blood) and nervous supply through the animal’s lifetime and the horns continue to grow during this time. Antlers, by contrast, are made of bone and develop from a point on the top of the male’s skull called the pedicle, rather than from the skull itself. The antler grows out of the pedicles and, during its formation, it’s covered with hairy skin, pink-to-grey in colour, packed with blood vessels and nerves (making them highly sensitive to the touch) called velvet – a stag in velvet is still sometimes referred to by the 16th Century term “pollard”. Should the velvet become damaged, the antlers can become deformed. The potential rejuvenating power of deer velvet has led to the marketing of tablets made from the velvet of farmed deer; the tablets are said to provide relief from various ailments spanning impotence to arthritis, whilst also having immune enhancing properties.

When the antler’s growth is complete, the velvet dries up and is shed (at this point, the deer is said to be “in tatters”) – this process appears to be under hormonal control and usually takes less than 24 hours. Deer antlers have androgen (male sex hormones) receptors and it appears that an increase in testosterone levels (probably related to increasing day length) causes the blood supply to the antler velvet to be severed, causing the velvet to die and dry out. When the antlers have been cleaned by the stag or buck (i.e. the velvet has been completely removed), the animal is said to be in the misnomer of “hard horn”. At this point, the antler is dead bone – it no longer has a nervous or blood supply and it cannot repair itself should damage occur. In her 1991 book Deer, biologist Norma Chapman explains that the basic antler pattern is genetically-fixed for a species, although the exact form and size of the antlers are affected both by parental characters and quality of food.

A study conducted by Uwe and Horst Kierdorf at the University of Giessen in Germany found that Roe deer antlers form by a different process to those of either Red or Fallow. It seems that whilst Red and Fallow antlers form by a process of modified endochondral ossification (i.e. a cartilage ‘model’ is turned to bone), Roe antlers form by intramembraneous ossification (i.e. connective tissue membrane is turned to bone). The study also found that although formation of Roe antlers was different, the antler growth proceeds by endochordal ossification.

Red stag in full antlerCasting of antlers is initiated by a drop in blood testosterone. Many studies on captive deer have demonstrated that if a stag is castrated while in full antler (i.e. hard horn), he will still cast and re-grow his antlers, but the velvet will never dry out and the antlers will not be shed. Under normal circumstances, antlers are shed and re-grown annually to coincide with the deer’s breeding season. Red, Fallow, Sika and Muntjac shed their antlers during April and May and the new growth is complete and cleaned by August/September. Roe shed their antlers in November/December and re-grow them over the winter and early spring such that they’re cleaned during April/May.

Shed antlers are sometimes eaten or licked by deer and other animals, providing a valuable source of calcium and phosphorous; hence, it is best not to collect antlers if you find them in the forest. Indeed, the antlers and velvet represent a veritable goldmine of nutrients for many animals. The antler itself is composed of various types of structural cells and there is an apparent negative correlation between calcium content and fat concentration along the antler – calcium levels increase towards the base of the antler, whilst lipid concentrations are highest at the tip. The antlers and associated velvet contain many of the essential dietary elements including calcium, phosphorous, sulphur, magnesium, potassium, sodium and iron. The velvet itself contains various amino acids (sub-units of proteins) including all eight essential ones (i.e. those that are required in the diet and can’t be synthesized by the animal).

For many decades scientists have hotly debated the function of deer antlers. The most widely accepted theory is that antlers evolved as weapons where deer compete for resources, predominantly (although not limited to) mates. In the first instance the antlers are a sign of fitness – they require a considerable amount of energetic and nutritional expenditure to produce and a large antler set typically represents an animal in good condition, although there’s an element of genetic control involved too. They can also be used by would-be interlopers to assess their chances in a fight and are used as physical weapons to both repel an attack from, and initiate a challenge to, a contender. Recent studies on moose in Europe have suggested that the antlers may also act as parabolic reflectors of sound, so moose with antlers have more sensitive hearing than those without. Logically, other species with palmate antlers (e.g. Fallow) may also gain a similar advantage. (Back to Menu)

For a more comprehensive overview of how antlers form and what function they serve, the reader is directed to the Antler Q/A.

Food and Feeding: Deer are omnivorous opportunists and will feed catholically on grasses, heather, lichen, shoots, bark, leaves, herbs, rushes, buds, nuts, fungi, fruit and berries; even holly and bramble.  They are typically mixed concentrate feeders, which means they select young shoots, young foliage, fruits and other high quality foods from which they can extract bone-building nutrients; “mixed” comes from their ability to switch between grazing and browsing. Carnivorous tendencies have also been documented in some species, perhaps most notably in Red deer who make it into the 2007 Guinness Book of Records under the unenviable title of “Most bloodthirsty ungulate”! The type of food consumed depends as much on location and season as on species.

Along with the more customary items in the diet, a range of inedible objects have also been recovered from deer digestive tracts; these include polythene bags, balloons, string and even a pair of disposable knickers! Unfortunately, these kind of objects can easily get stuck and cause a blockage. In her 1991 book Deer, Norma Chapman notes that a study of more than 80 Fallow deer stomachs collected in Essex found that they all contained at least one foreign object.

Deer are ruminants, which means that they “chew the cud” -- indeed, ruminant stems from the Latin ruminatus, meaning “to turn over in the mind” or “chew the cud” -- where cud is thought to have roots in the Old English cwidi, meaning “what has been chewed”. Moreover, deer are poly-ruminant, which means that they have multiple sections to their stomach – four in the case of cervids. Starting at the oesophagus (throat), the chambers are named: the Rumen; the Reticulum; the Omasum; and the Abomasum, which empties into the small intestine.

Diagram of deer stomach
Highly simplified representation of the deer stomach, showing sections in order from oesophagus (food in) to small intestine (chyme out).

Food passes down the oesophagus into the rumen, where it sits and becomes mixed with microbes. An expansion of the chest produces a vacuum in the upper rumen and allows some of the plant material to be sucked into the oesophagus, where peristaltic movements force a clump of cud (called a bolus) up into the mouth. When in the mouth, the bolus is pressed against the roof by the tongue and excess water is swallowed before chewing recommences. In his 2007 book Deer Watch, Richard Prior notes that cud chewing seems to be a relaxing activity for deer; they lie with eyes half-closed and a slight hiccup and ripple in the throat signals the re-arrival of a ball of food.

Deer possess a brachyodont dentition, whereby the molars have low or short crowns and well-developed roots. In each side of a deer’s jaw the three incisors and (in most species) canine are separated from the three premolars and three molars by a large gap; the crowns of the upper teeth fit neatly into the teeth of the lower jaw. The tooth arrangement, coupled with adaptations to the jaw musculature allows the lower tooth rows to move across the upper ones such that deer chew with a “sweeping grinding [side-to-side] motion”. This ensures the plant material is ground against the ridges of the molars and premolars (collectively termed the “cheek teeth”). The cheek teeth break up the cell walls, releasing the digestible contents, while the large molars serve as a mill on which to grind plant material into fine particles. The food is then re-swallowed.

The grinding process serves to increase the surface area of the plant material available for the microbes in the rumen to work on, while the act of chewing stimulates saliva that acts as a buffer to the acid in the rumen (which must be kept within fairly tight limits of pH). At the same time, microorganisms are regurgitated with the cud and so become more thoroughly mixed with the digesta as it’s chewed. The process of chewing the cud also increases the effective length of the digestive tract, meaning that the microbes have longer to breakdown the plant material. Despite all this, overall, very little actual digestion takes place in the rumen (it is primarily a holding tank), although a reasonable amount of fatty acid are liberated from the food here; some authorities estimate that as much as 40% of the deer’s energy may be obtained by absorption of fatty acids and sugars from the fermentation of cellulose through the rumen wall.

Upon leaving the rumen, partially digested food (called chyme – pronounced “kime”, from the Greek chymos, meaning “juice”) passes through into the reticulum, where it's strained – it should be noted that the rumen and reticulum are considered the same functional space, because material can move back-and-forth between the two (for this reason, they are sometimes collectively referred to as the reticulorumen). The reticulum lining is covered with a framework of ridges, forming a honeycomb pattern and serving to increase the surface area over which volatile fatty acids can be absorbed. The reticulum is effectively a fermentation vat, containing what Rory Putman describes as “a murky suspension of tiny food particles and micro-organisms” in his The Natural History of Deer. Within the reticulum sits the ruminal mat, which is a thick mass of partially-digested fibrous material. As material is regurgitated and re-swallowed, there comes a point where the particles are sufficiently small and dense to pass down through the mat into the ventral sac and from there through the reticulo-omasal orifice into the third section: the omasum.

Sika deer eating acornsThe omasum has a heavily-folded lining allowing for between 60% and 70% of the water to be absorbed, along with inorganic minerals (e.g.  magnesium) and any fatty acids that haven’t entered the bloodstream through the reticulorumen. It seems that larger particles can be pushed back into the reticulum for further digestion, should they make it through the reticulo-omasal orifice. From the omasum, the chyme moves into the fourth, and final, chamber: the abomasum.

It is in the abomasum that the majority of digestion takes place and where gastric juices (including hydrochloric acid) are secreted – this section is often referred to as the “true stomach” because it is the equivalent of the stomach in monogastric animals, such as humans. As such, the digestion of fats, carbohydrates and proteins progresses as it does in other vertebrates and the products are sequestered into the bloodstream. The epithelium (lining) of the abomasum has gastric pits called "foveolae" with gastric glands underneath them, that contain hydrochloric acid-producing parietal and zymogenic cells (that make digestive juices), similar to our stomachs.

The majority of saccharides (produced from breaking down of sugars and starches), amino acids and peptides (break down products of proteins) are taken up by the microorganisms doing all the work in the rumen and put towards their growth and multiplication. As the microbial population grows, some invariably get washed out of the reticulorumen with the chyme, where they’re killed by the abrupt change in acidity and are digested – it is estimated that up to 90% of the animal’s amino acids are obtained in this way (the microbes also represent an important source of glucose in starch-poor diets). Deer are thus sometimes said to ‘farm’ microorganisms and obtain their essential amino acids by digesting the microbes leaving the reticulorumen. The food finally passes out of the stomach and into the small, and then large, intestine where further digestion and absorption takes place.

So, why do deer need such an elaborate digestive system? Well, unsurprisingly, the answer lies in the type of food they eat: plant material. No mammals are able to efficiently break down plant matter; we don’t have the correct enzymes for the job. Consequently, when we eat fruit and vegetables, all we can get out are ‘goodies’ in the liquid contents of the cell – unfortunately, this represents only about 20% of the total energy contained in the material because most is bound within the fibrous cell wall. The cell wall of plants consists of four main compounds: cellulose; hemicellulose; lignin; and pectin. Thus, in order to get at this energy (in the form of proteins, fats and sugars), we’d need to be able to break down both the tissue itself and the polymers (long-chained molecules) that make it up. The problem is that, while the tissue itself can be broken down fairly effectively by chewing, the aforementioned compounds are ‘tough’ and not at all easy to digest.

GrassesAs we have seen, deer (and other ruminants) maintain populations of microorganisms in their stomachs, which can breakdown the cellulose and other structural compounds to release fatty acids, amino acids, peptides, sugars and various simple nitrogenous compounds (e.g. ammonia) that the deer can absorb and use for energy. Using microbes in this way is referred to as syntrophism. This syntrophic arrangement with the bacteria and protozoa make ruminants some of the most effective animals on the planet at converting the polysaccharides (long-chained sugars) in grass to protein (i.e. tissue mass). So effective is the process that ruminants can access between 50% and 60% of the total energy contained within the plant material. What this means in practice is that deer are able to take advantage of nutritious young herbage, but are also able to make the best of even low quality forage. Obtaining essential amino acids, vitamins and minerals via digestion of microbes means that ruminants can ‘divvy up’ resources to a much finer scale, allowing species to specialise on a narrow range of plants. Additionally, by making use of a storage vat (the rumen), deer can eat considerable quantities at a single sitting and retire to a safer spot (i.e. away from predators) to digest the meal.

The process of rumination is certainly a good way of utilising the energy available in the structural tissue of plants. However, it is not without its disadvantages. Efficient utilisation of cellulose takes time and to get access to 60% of the bound-up sugars may take up to 80 hours, which means the animal must feed almost constantly and is forced to accept lower quality forage; high quality browse/graze is likely to be patchy and with digestion times of this length, the animal can’t afford to spend the time searching for them. Deer typically have small rumens, which allows for faster digestive throughput -- meaning they can feed less often and spend more time searching out good quality food -- but at the price of a less efficient digestion of cellulose. As we shall see in a moment, a further disadvantage of this type of digestive system is that it becomes highly food-dependent – the microbial community in the stomach is tailored to digest specific types of plant material, which means that deer cannot rapidly switch foods.

I have used the term “microorganisms” repeatedly in this section as an umbrella term for all the microscopic critters that work to break down plant material eaten by deer. However, there are actually five groups present in the reticulorumen. Collectively, bacteria and protozoa account for 40% to 60% of the microbial mass and, while bacteria do most of the digesting, the protozoa eat the plant material and degrade the major plant parts; protozoa also help maintain the gut bacteria population by grazing on them. In recent years, there has been much research on the microbial communities of ruminants and there are now in excess of 50 genera known from ruminant digestive tracts. Along with bacteria and protozoa are fungi, which make up about 0% to 10% of the microbes, depending upon the fibre in the diet, and are important digesters of lignin and hemicellulose. Archaea (about 3% of the microbes) serve to reduce gaseous build-up by converting methane to carbon dioxide, which can be transported in the blood to the lungs for removal – methane must be eructated, or “belched” out. Finally, there are the viruses, which aren’t involved in the digestion of plant matter, but to help keep the other microbes in check.

Roe buck browsing treeIt seems that gut microbes can be inoculated (introduced) into the neonate (newborn) rumen through various processes. Charles Robbins, now at Washington State University, reported in his 1983 book Wildlife Feeding and Nutrition, that inoculation of bacteria into the rumen of newborn ruminants is often dependent on the feed ingested by the mother during suckling and the contact the young has with its mother’s faeces.  Overall, the microbial community fluctuates with the diet of the host – different microbes are required to breakdown different types of plants.  Consequently, a ruminant eating grass as the staple of its diet may have different gut microbes to one that feeds primarily on browse, which poses a problem should either animal find its food source gone. A ruminant that has spent all summer feeding on grass will not have the microbial flora and fauna needed to digest woody material.  Unfortunately, the animal doesn’t know what types of microbes it has in its rumen and so will usually eat unsuitable foods if presented with the opportunity (especially if its normal food is scarce).

One additional curiosity of the deer digestive system is the lack of a gall bladder. In most mammals, the gall bladder produces bile salts that act to emulsify and break down fats. Some authors have postulated that, because plant material is typically low in fats and the fatty acids released by microbial digestion can be absorbed through the reticulorumen, the need for fat digestion is no longer present.

Finally, let us take a moment to consider the need for water. Deer do drink (muntjacs are rarely found far from water), but most of the water is supplied in their food. Moreover, ruminants have a highly efficient water conservation technique linked to their ammonia cycle. Simply put, the fermentation of protein leads to the production of ammonia, which is transferred (via the bloodstream) to the liver and converted to the less toxic waste product urea; the urea is then transferred back to the stomach where it is assimilated (i.e. used as food) by the microbes. The recycling of urea in this way means that it doesn’t have to be sequestered from the bloodstream (by the kidneys) and diluted with water to be excreted in urine – this saves a considerable amount of water.

Feeding behaviour typically cycles between periods of grazing/browsing and ruminating. There are peaks in the feeding behaviour at dawn and dusk and much rumination takes place during daylight hours. More specific details can be found under the “Activity” section of the individual species profiles. (Back to Menu)

Senses

Vision: The subject of how deer perceive their visual world has been the object of much interest in recent years. The anatomy of a deer’s eye follows the same basic scheme as those of other vertebrates, although there are some subtle differences – one relates to the UV filtering ability of the lens, which we shall come to shortly. Deer eyes have an oval (i.e. slot-shaped) pupil that is orientated laterally, such that the pupil runs parallel to the horizon; this may help the deer focus on the entire horizon at once, rather than relying on the spot-focus afforded by a circular pupil (as humans have). Behind the retina -- in the choroid (or vascular) layer -- is a layer of reflective cells common to all nocturnal mammals, collectively called the tapetum lucidum (from the Latin meaning “bright carpet”). The tapetum cells reflect light back into the eyeball that would otherwise be lost into the skull, thereby increasing the amount of light the eye can use. The tapetum is also responsible for the “eye-shine” familiar to hunters and often unfortunate car drivers; in deer, the eyeshine is typically orange, although the effect is a form of iridescence, so the colour will vary according to the angle of the light.

The eyes of deer are situated at either side of the head, which gives the animal a wide field of view. In his fascinating 2006 book Deer of the Southwest, Arizona Fish and Game Department biologist Jim Heffelfinger writes: “A deer’s eyes are set on the side of the head, allowing them to monitor almost a complete circle (310o)”. The visual field of 310-degrees seems in accordance with other ungulates: horses, for example, have a visual field of some 350 degrees – to put that in perspective, humans have a visual field of about 180o. The drawback to having the eyes situated on the side of the head is that you lose binocular vision, which means severely limited depth perception. For deer, it seems reasonable that being able to see what’s sneaking up from pretty much any angle would be of greater benefit than being able to accurately judge how far away the ‘sneaker’ is.

Fallow deer eyes

For many years deer were thought to have a retina containing only rod cells that provided pretty poorly defined, black-and-white, vision. Rod cells are used for low-light vision (far fewer photons of light are needed to stimulate a rod cell than a cone, which means that it works well in low light conditions) and provide low resolution monochromatic vision. Cone cells, by contrast, afford colour vision and clarity (i.e.  fine detail) in good light conditions. So, if a deer had a retina composed entirely of rods, the animal would see a rather blurry black-and-white picture of the world – a stationary object would be difficult for the animal to resolve. Field observations by stalkers who were able to approach within close quarters of deer, provided they froze when looked at, seemed to back-up the idea of poor vision in these animals. In 1978, however, Donald Witzel at the US Department of Agriculture published the results of a retinographic survey on White-tailed deer (Odocoileus virginiarus) in the American Journal of Veterinary Research. Upon studying the retina of these deer, Witzel found both rod and cone cells, suggesting that deer may have better vision than they were originally given credit.

Unfortunately, the study of deer vision -- indeed, deer senses in general -- have been rather restrictive. The majority of studies have been conducted on Fallow (Dama dama) and White-tailed deer and it is arguably unwise to extrapolate these results to other species.  Nonetheless, many (although, not all) subsequent studies on these two species have confirmed Witzel’s findings. In 1994, for example, Gerald Jacobs and colleagues at the University of Georgia in Athens published a paper in the Journal of Comparative Physiology detailing aspects of the retinal sensitivity of Fallow and White-tailed deer.  Professor Jacobs and his co-workers found that these species had both rod and cone cells – the rod pigments had a maximum sensitivity (called a “lambda max”) at 497 nm, which is in the blue spectrum. The biologists found two types of cone cells or, more accurately, cone cells that had one of two different pigments in them: one had short wavelength sensitivity (450 – 460 nm, again in the blue) and the other had sensitivity in the middle wavelengths (537 nm for White-tailed and 542 nm for Fallow, these are in the green part of the spectrum). So, it seems that these deer are able to detect colours in the blue-green part of the electromagnetic spectrum (similar to a human with deuteranopia, or red-green colour blindness), and that the rod cells may help the deer discriminate between shades of these colours. These findings are not a surprise to most biologists – deer are predominantly active from dusk until dawn and an ability to discern blue light is a great aid to low light vision.

Perhaps more interesting than deer being able to discern hues of blue and green is their vision in the ultraviolet part of the spectrum. While dissection of the deer eye reveals a granula iridica (sometimes called corpus nigrans – a projection of the iris into the eye that acts as something of a sunshade to reduce glare in bright light), deer don’t appear to possess a UV filter. Adult humans -- excluding those who are aphakic (have a missing or damaged lens) -- cannot see light in the ultraviolet spectrum (10 – 400 nm); the human lens contains UV filters (most notably 3-hydroxykynurenine, or 3OHKyn for short) that prevent light of this wavelength entering the eye. Deer, by contrast, don’t have this yellow pigment, which suggests that they may be sensitive to ultraviolet light.  Indeed, an entire industry has sprung up in America offering hunters washing powder that doesn’t leave particles on the clothing that would otherwise reflect UV and make the person positively glow. I should mention that there is still some debate over this idea; Prof. Jacobs and his team failed to find any significant response of their deer retinas to UV light.

Electromagnetic Spectrum
The electromagnetic spectrum (EMS). The visible spectrum (highlighted green above) sits between the ultraviolet (UV) and infrared (IR) wavelengths and is shown expanded above the main spectrograph. Visible light roughly covers the wavelengths of between 380nm and 750nm. Graphic based on various sources, including the Antonine Education Website.

As you’ll no doubt have noticed by now, most of the experiments to-date have involved analysis of the deer’s retina, which runs the potential risk of overlooking rare cone cells. Perhaps more importantly, the mere presence of cone cells on the retina tells us nothing of the deer’s ability to apply any colour vision they may afford. In a bid to circumvent some of these problems, a team at Stockholm University’s Zoology Department took a different approach. The researchers, fronted by Bjorn Birgersson, assessed the colour vision of Fallow deer through a series of behavioural tests; their results were published in the journal Animal Behaviour during 2001. The team found that all four individuals were able to discriminate green from grey, irrespective of brightness.  It appears that Fallow deer can use limited (dichromatic) colour vision to discriminate between objects, by generalizing over slightly different colours in the green spectrum. The scientists suggest that blue/green-shifted colour vision may be useful in discriminating between different plant species or different parts of plants that might be of variable nutritional (or toxic) value.

The results of the 2001 study seem to fall in line with circumstantial evidence of colour perception in deer. In his 1995 book, Roe Deer: Conservation of a native species, Richard Prior recounts some fascinating stories of the visual acuity of Capreolus capreolus. Prior tells of one captive Roe that reacted to the different coloured coats worn by its keeper; it paid no attention to a blue coat, but fled “crying in fear” when the keeper wore a red coat. In addition, Prior notes how, over the years, many Roe keepers and stalkers have become convinced that this species is able to recognise familiar clothing. In the end, however good one considers deer vision to be, I think that Richard Prior sums the situation up succinctly in his Deer Watch book.  In this fascinating guide to deer and deer stalking, Prior points out that deer flee through often dense woodland, so their eyesight can’t be that poor! (Back to Menu)

Fallow deer noseOlfaction (Smell): Most professional deer stalkers will tell you how difficult it is to gain an appreciation of how sensitive a deer’s sense of smell is – while searching for deer, the slightest change in wind direction or air eddy in the forest can scupper your chances for the rest of the day. The problem is compounded by the fact that humans typically have a very poor sense of smell. Sadly, in the same way that studies on the visual capabilities of deer have only been conducted on a few species, studies on cervid olfaction are similarly restrictive.

We can gain an insight to the importance of scent in a deer’s world by looking at the structure of the animal’s brain in conjunction with that of its nasal cavity. Deer have larger olfactory bulbs (the scent-processing parts of the brain) than we do; they also possess a considerably greater surface area of olfactory epithelium than humans.  In a study of the olfactory epithelium of the Roe deer published in 1975, German anatomist Albert Kolb found that the average area of olfactory epithelium was 90 sq-cm (14 sq-in) – if we compare that to an adult human, which typically has about 10 sq-cm (1.6 sq-in), we can see that a Roe deer’s sense of smell is potentially nine-times more sensitive than ours. Coupled with larger bulbs and increased epithelial area, deer also have a long nasal passage, terminating in a moist rhinarium (nose).  A moist nose helps improve the sense of smell; volatile scent particles stick more easily to wet noses, while the side of the nose being cooled by the prevailing wind helps the animal establish the direction from which the scent has come. Studies in domestic dogs have found that wet mucus on the nose can also help to pre-sort odour molecules hitting the nose, by slowing down their passage into the nasal canal.

Early behavioural studies also attest to the ability of deer to find and assess food by smell. In 1934, Joseph Dixon published a paper in the journal California Fish and Game detailing the results of his studies on the food habits and life history of Mule deer (Odocoileus hemionus) in California. Dixon found that his subjects were able to tell good acorns from those with worm infections and those that were hollow by smell alone. Similarly, in a 1977 special report of Arizona Game and Fish Department, Theodore Knipe described how White-tailed deer were able to locate oak leaves and acorns under several inches of snow using cues that could only have been olfactory.

In addition to the main nasal process, deer have another scent-detecting gland -- sometimes referred to as their “second nose” -- called the vomeronasal organ (often shortened simply to VNO). The VNO was first described by Danish anatomist Ludvig Jacobson (as such it is sometimes referred to as the "Jacob's Organ") in 1813 and, in deer, it takes the form of a diamond-shaped lump of tissue at the roof of the mouth. The nerves run from the VNO, along the nasal septum, to the vomeronasal bulb (sometimes called the 'accessory olfactory bulb'), which contains the same type of sensory cells as the main olfactory bulb. The VNO is considered to play a role in assessing the sexual readiness of deer and perhaps helping to sync the male's reproductive condition to that of the nearby females. It is certainly interesting that the brain connections for the nasal and VNO nerves are apparently different. As University of Georgia deer biologist Karl Miller points out in his Deer Talk With Their Noses article, the VNO connects to the part of the brain that controls the reproductive condition of the deer, rather than connecting to the same part as the nasal passage.

Studies on White-tailed deer have shown that, although the VNO is used to sample urine in order to assess a female's impending oestrous, even if the organ is removed, the deer are still able to tell when a female is in season. This is in contrast to many other studies that have shown how a damaged or missing VNO can lead to suppression of reproductive activity – this was first demonstrated in 1953 with male guinea pigs, which failed to mount females when the VNO was impaired.  The male deer samples the female's urine using a flehmen response, where he curls his upper lip and lifts his head up into contact with the urine stream – the animal may also wrinkle its nose and cease breathing for a moment. Flehmen is frequently observed in rutting deer, but is common among the ungulates and other mammals, including cats. It is theorised that the act of flehmen serves to move fluid-based pheromones (i.e. in the urine or vaginal secretions) from the mouth to the VNO. In his 'Deer Talk' article, Dr Miller notes that "Deer use the VNO exclusively to analyze urine". (Back to Menu)

Roe deer head showing earsAudiology (Hearing): In his 1995 book The Roe Deer, Richard Prior draws attention to Capreolus having “large ears constantly moving”.  Indeed, even when their owner is at rest, a deer’s ears are scanning for any unrecognised sounds. The ears of a deer are highly (and independently) mobile and can be rotated almost 180-degrees; at the same time, their large size and cupped structure allows for the efficient gathering of sound waves. Despite the observations we can make on the physical characteristics of deer ears, data on hearing thresholds are somewhat lacking – as before, where we have data they generally pertain to the White-tailed deer.

In a series of experiments on hand-reared White-tailed deer held at Texas A&M University’s College of Veterinary Medicine, biologists sought to establish the hearing frequencies in order to assess the effectiveness of whistles as deer deterrents (see Interaction with Humans). The study, led by Ken Risenhoover, measured what are called “evoked potentials” – these are electrical responses of nerves to a stimulus, so they wire the deer up to an audiograph and play pings of varying frequencies and volumes to it through headphones. From these data it appears that the deer had the greatest hearing sensitivity between 1 and 8 kHz, with a peak sensitivity at 4 kHz and a range from 0.5 to 12 kHz (at 85 dB). In the summary of results on his website, Risenhoover notes “recorded deer vocalizations reported from the literature … range between 1 and 9 kHz”, so the main hearing sensitivity ties in quite nicely with the call frequency data.

A similar study, led by Gino D’Angelo at the University of Georgia and published in the Journal of Wildlife Management during 2007, found their White-tailed deer were able to hear in the range of 0.25 to 30 kHz, with peak sensitivity between 4 and 8 kHz. These findings compare favourably both to Risenhoover’s data and to a study of Reindeer (Rangifer tarandus) published by Kjetil Flydal and colleagues in 2001, which found that this species could detect sounds within the range of 70 Hz to 38 kHz, with a peak sensitivity at 8 kHz.

So, the upshot of these studies is that deer have a hearing range similar to that of humans (typically 20 Hz to 20 kHz), but with the ability to detect sounds within the low ultrasonic (20 kHz and above).  (Photo: A Roe doe, Capreolus capreolus, illustrating the large, highly mobile, ears). (Back to Menu)

Behaviour and Sociality: In his Deer of the World, Valerius Geist notes that, during their radiation from tropical to colder climates, deer evolved from solitary saltatorial (‘hiders’) animals to gregarious cursorial (‘runners’) ones with complex antlers and striking changes to their tail and rump. Indeed, most species of deer in Britain form either social or family groups (in some cases, the group may be both social and familial).

Fallow bachelor group
A bachelor group of Fallow bucks.

Roe deer typically form small family groups (male, female and young) and males establish territories during the rut; larger, but unstable, groups may be formed during winter. Muntjacs may be either solitary or may establish small family groups (male, female and dependent young) and maintain a territory from which interlopers are expelled. Red deer hinds are found in matriarchal groups throughout the year and stags congregate in loose ‘bachelor’ groups outside of the breeding season while their antlers are shed and re-grown – Red stags are antisocial towards other males during the rut. Sika hinds form aggregations during the rut, but outside the breeding season they are surprisingly solitary (given the gregarious nature of other Cervus species); they tend to be found either solitarily or accompanied by a single calf. Fallow deer are gregarious, with does forming fairly stable groups of up to five or six, typically related, individuals (these may combine at favourable feeding sites to form herds of up to 200 deer); the sexes are typically separate, although doe herds may contain males of less than two years old. Fallow bucks are less social than does, typically found either solitarily or in small groups.

Clashing Fallow bucks
Rutting behaviour among males -- as in these Fallow bucks -- is highly ritualized, with much roaring and parallel walking. When these, more passive, means of establishing dominance fail, a spectacular clashing of antlers ensues, with each animal trying to push the other backwards.

A deer’s world is heavily based around scent – all deer possess scent glands, the products of which are used to mark themselves and objects in their range/territory. Taking the Cervidae as a whole, at least 13 sites containing scent glands have been identified, although most deer have varying combinations of these, which may be active all the time or only during certain seasons. A typical scent gland is composed of a hair follicle into which fatty acid secretions (from a sebaceous gland) are made. Scent glands have been seen to gape during periods of high emotion (such as during the rut), which implies a social context to the scent signals. In his section on deer in the Encyclopedia of Mammals, Geist notes that as a general rule of thumb, small species mark the ground and vegetation with glandular secretions, urine and/or faeces, while larger species mark themselves. More specific details of the scent glands possessed by the different species can be found on their profiles, along with information relating to their use.

In addition to scent, sound is also an important component of a deer’s world. In her 1962 book, The Language of Animals, Millicent Selsam writes of how it is signals of voice and gesture that keep herds of deer coordinated. Selsam points out how the dominant cow in a herd of American elk (Cervus canadensis) can make the whole group change direction with the motion of her head and neck, or flee when she gives a warning bark. Male deer emit various types of roar (depending upon the species) associated with the rutting period; these calls convey a wealth of information about the caller and, in some cases, may serve to spur females into oestrous. There are also various calls used by mothers and their young, from soft bleating or “pheep” utterances to loud distress calls that can bring several mothers (all with young in the area) to investigate.

Perhaps the most obvious deer behaviour is that of the rut. It is believed that the word “rut” is Middle English from the Latin rugire, meaning ‘to roar’. The rut is the breeding season, where males compete for female attention. During this period, males become aggressive to other males and very attentive to the females – there is also typically much vocalisation, sparring and marking of territory/stands. Challenges typically take the form of roaring, parallel walking (to assess size) and clashing of antlers, during which each deer will try to push the other off balance. Sparring in this way allows the settling of disputes with little (typically no) bloodshed. Some deer watchers report that sparring partners may form ‘friendships’ and travel, feed and rest together. In the case of Muntjac, the bucks strike at each other with their canine teeth.

Roe buck in silhouetteIn all deer species found in Britain, the rut is controlled by the females. Red stags defend areas of prime grazing land and, by doing so, have access to the majority of the females. Fallow bucks typically (although not in all cases) form leks where they congregate to display to the does, who wander around the males and choose who to mate with.  Roe bucks establish territories into which does are pursued in relentless chases terminating in the copulation. Sikas establish rutting stands that sit between hind resting and feeding sites; the stags stand in these areas and advertise their availability to the passing hinds.  Muntjacs are the only deer species in Britain to breed throughout the year; bucks will mate with any females whose range overlaps with his and may possibly travel short distances out of his territory looking for does. The rut represents a considerable energetic investment for males, which keep up the activity day and night for several weeks, and often leaves the stag/buck physically exhausted.

Other behaviours include bark stripping; this tends to be limited to the rut as it’s often associated with cleaning of antlers and marking of territory, although deer do occasionally strip and eat bark. Most of the damage tends to be done in commercial plantations, where deer may eat leading shoots and lateral buds of developing saplings if adequate (often costly) preventative measures aren’t taken.

Deer will “pronk” (a movement best described as a bounce, with all four feet off the ground at the same time - see below, left) to alert others to danger and in some cases when moving uphill. Indeed, while moving around their range, deer leave various signs of their presence.  These include chewed and frayed vegetation; where deer densities are high a browse line may be obvious in the treeline. Deer are also creatures of habit and will often create well worn footpaths between favoured resting and feeding sites. Along these footpaths one can often find their footprints (called slots), which can tell you a little about how fast they went through there; when walking the hind feet “register”, which means that they step into the slots left by the front feet (this doesn’t happen when the deer runs). Along tracks and around feeding and bedding sites it is common to find scat, which are small black, dark brown or dark green (depending on the diet) cylindrical pellets – although they contain undigested plant material, this is generally not visible without dissection. During the breeding season, the larger deer species create rutting scrapes, which are shallow depressions in the ground varying from a foot to several metres in diameter; sometimes a distinct ring of trampled vegetation can be seen around a tree trunk or bush to indicate a Roe mating chase. (Back to Menu)

Pronking deer cartoonDeer scat
Deer occasionally 'pronk' or 'stott', typically when moving uphill or when fleeing from a disturbance. Evidence of their presence can be found throughout the deer's home range - scat, either as a pile of disassociated pellets or as a clump ('crotties') is a good sign there are deer in the area. The coin in the photo is 2cm (three-quarters inch) in diameter.

Interaction with Humans: Deer are possibly more deeply rooted in human history, culture and art than any other of our wild mammals, even the Red fox! Consequently, the subject of how these animals interact with us is something of a mammoth one. In a bid to restrain this article, I have divided the interactions into seven groups and have provided a brief summary of each; each group is really a thesis topic in its own right. Nonetheless, most of the groups have a Q/A associated with it, which will cover the topic in more detail – please follow the links at the bottom of the page to the relevant Q/A. The exceptions are Hunting & Deer Parks, which are covered in more detail on the various species profiles, and Art & Culture Subject, which is covered fairly comprehensively, with crests, by Wikipedia.

Hunting and Deer Parks: In his 2002 Fauna Britannica, Duff Hart-Davis provides a fascinating overview to the history of deer parks and farming in the United Kingdom and the reader is directed there for further details on the topic.

There is some debate as to when and where the farming of deer first took hold. Deer farming has been variously cited as having its origins in China or New Zealand and while the Food and Agricultural Organization suggest that deer farms have been established for “a century or more”, some authors report deer farms in New Zealand for more than five thousand years! Wherever it first began, New Zealand is currently the largest deer farming country in the world, with an estimated 1.7 million animals. In the UK, the idea of keeping deer in parks probably dates back to the Romans, who brought Fallow deer with them on their voyages.  The idea is implicitly simple; deer are generally contained within a fenced or walled boundary. I say generally, because deer were known to escape over or through the fences (leaving the park to mate with wild deer). Large ‘steps’, called “deerleaps”, were incorporated into the fence line of many parks that allowed deer (returning and wild animals) to easily jump into the park, but not jump out again. Where deer were held close to grand estates, structures called “ha-has” were erected to stop deer getting into manicured flower gardens and lawns – these structures were basically long ditches separating the deer park and grounds that had a brick wall on one side and couldn’t be seen from the main house (so as not to spoil the view).

Deer parks seemed to gain popularity since the Roman period and, by the time the Domesday Book of 1085 to 1086 was written, there were at least 31 parks in Britain. During the Middle Ages, Britain boasted some 2,000 deer parks that were predominantly used as a source of animals for hunting. Unfortunately, the Crown seemed to lose interest in deer hunting and this led to forests being cut down, sold off or divided up by a series of Enclosure Acts. A reprieve came in the late 1500s, when Queen Elizabeth restored some of the interest in forestry as a source of timber. By the mid-17th Century the number of parks stood at around 700 and some fell into private ownership. Indeed, Richmond Park in London was designated a royal deer park in 1625 when Charles I moved Parliament to Richmond in order to escape the plague. In 1637, Charles fenced off the park (an unpopular move) and hunts on horse back were conducted within it until about 1750 (well after Charles was beheaded).

The number of deer parks in Britain suffered further declines at the hands of the Roundheads (or Parliamentarians) who -- under the orders of Oliver Cromwell -- destroyed many between 1653 and 1658. According to Hart-Davis, Joseph Whitaker (writing in 1892) only listed around 400 deer parks in Britain. During the 20th century, the number of deer parks fluctuated in accordance with the need for timber and farmland during the World Wars. Up until the 1970s, deer parks had been used predominantly as a source of meat for the monarchs’ tables (Christmas hampers, wedding feasts, etc.) or, in the case of Woburn, to hold the growing collection of animals owned by the 11th Duke of Bedfordshire.  Today, many of the remaining deer parks are open to the public. During the 1970s, deer parks in which deer were bred exclusively to slaughter for meat, and had no public access, were formed – these were the true deer farms.

Fallow does at Petworth Park
Deer parks, allowing members of the public close encounters with deer and providing a ready source of low fat meat (venison), can still be found throughout Britain. These fallow hinds form part of the herd kept at Petworth Park in Sussex.

According to the British Deer Farmers Association (the nationally recognized body representing the deer farming community since 1979) in Derbyshire, there are presently about 300 deer farms in the UK rearing some 36,000 deer. This may seem like a reasonably high number, but it actually represents about 0.6% of the animals currently farmed in the UK. Of the deer species farmed, the majority (just under 80%) are Red, with the remaining 20% being Fallow – Roe deer aren’t generally considered a gregarious species and hence aren’t widely farmed. Stags are typically culled at between 15 and 17 months old, while hinds are dispatched slightly later, at about 27 months. The manner in which deer are kept, handled and culled is partly governed by the Farmed Game and Fresh Meat Regulation (1995); in the UK, the protocols of this (and other applicable animal welfare directives) are policed by the Department for Environment, Food and Rural Affairs (DEFRA).

Some parts of the deer invariably make their way into the various potions and medicines on the market in the Far East but the majority of the meat ends up in supermarkets as venison. Today, if asked what venison is, most people would probably say it was deer meat.  Archaically, however, the term "venison" (from the Latin venari, meaning “to hunt”) actually covered the meat from any game animal. In his book, Hart-Davis provides some comparative nutritional details of deer and other meats. Going by these figures (which are similar to those provided for a 54g lean deer loin steak by nutritionaldata.com), a deer steak contains about 1.6g of fat per 100g of meat (so it is ~1.6% fat). The comparative value for pork is 15.2%, for lamb it’s 12.3%, for beef it’s 12.9%, while for (whole) chicken it’s 13.8% – of course, these values will vary according to the cut of meat as well as the conditions in which the animal was kept. The British Deer Society point out that venison is lower in fat than a skinned chicken breast, while also being high in iron and low in cholesterol.

Deer have been on Man’s menu for as long as the two have lived together. In his The History of British Mammals, Derek Yalden points out that there are remains of Red deer that appear to have been taken by human hunters, which date back to the Wolstonian and Ipswichian Glaciations; the former ended about 130,000 years ago. Recent archaeological data presented as part of the London Natural History Museum’s Ancient Human Occupation of Britain Project, suggest that there were several ‘waves’ of attempted human colonisation in Britain, starting about 700,000 years ago. However, it appears most attempts were unsuccessful (owing largely to freezing conditions) and that humans didn’t really get a decent foothold until about 12,000 years ago.  Indeed, in his opus, Yalden also notes that, based on remains from Star Carr in Yorkshire (which date to 9,488 B.P.), both Red and Roe deer were the prey of these Mesolithic hunters. It seems that the hunters weren’t only after the meat – remains from the Yorkshire site suggests that antlers were used as the raw materials for various tools and clothing accessories.

It seems curious that, even despite the long history of deer hunting in the UK, deer aren’t currently officially classified as game species, which means that they’re not included in the Game Act of 1831.  Nonetheless, hunting as a sport seems to have maintained its popularity throughout the centuries, although the hunting of deer has also typically been the preserve of the rich and royal. Indeed, while the Romans and Anglo-Saxons apparently lived by the rule of res nullius -- Latin meaning “nobody’s thing”, so an animal killed by a hunter belonged to that hunter, regardless of whose land it was killed on -- this was not something that the Normans appreciated.

White Fallow buck in New ForestMany of the forests we have today started life as royal hunting estates. One of the most famous of all such estates is the 571 square kilometres (141,000 acres) of Hampshire that forms the New Forest (or Nova Foresta, as the Domesday Book of 1086 lists it). The Forest was declared a royal hunting preserve by William the Conqueror during 1079; William and his party were the only ones allowed to hunt in the Forest and there were stiff penalties -- described as “savage forest laws” by Edward Rutherfurd in his riveting novel The Forest -- for any interlopers hunting deer there. Deer hunting, largely on horse-back and later horses accompanied by hounds, persevered in the Forest until about 1997, when the last New Forest pack of stag hounds was disbanded. The subsequent implementation of the Hunting Act in 2004 has changed the way hunting takes place in the UK. Today, the majority of deer hunting in the Forest (as elsewhere) is conducted by deer stalkers -- either employed by, or licensed by, the Forestry Commission -- and is aimed more at control of deer populations than the form of trophy hunting seen in the USA.

Deer have little respect for human boundaries and, as such, move over various areas of private land, which makes coordinating effective population management challenging. In the UK, the Deer Initiative is involved in consulting with landowners and councils on the management and welfare of deer populations. In Scotland, the Deer Act of 1997 gives the Deer Commission of Scotland powers to regulate deer management in the country, while deer management falls under the jurisdiction of the National Parks and Wildlife Service in the Republic of Ireland.  Currently, there are no limits set on the numbers of deer that can be shot by stalkers and landowners, but the Deer Acts do stipulate the way hunting must be conducted, including open and closed seasons and the calibre of weaponry used. Recently, however, owing to a substantial rise in deer numbers, it has been proposed that the closed season should be removed in Scotland; this would allow Red deer to be shot all year round. While this may seem like a sensible idea if we are to reduce deer numbers, some biologists have raised concerns. In the current (July 2009) issue of BBC Wildlife Magazine, Deer Commission for Scotland biologist Colin McClean writes of his fear that removing the closed season will lead to both the overexploitation of stags and the underexploitation of hinds. This, McClean writes, means that “Scotland’s deer population will end up less economically valuable, but still growing”. (Back to Menu)

Damage to Agriculture: Back in 1998, the Ministry of Agriculture, Fisheries and Food (now known as DEFRA) commissioned a study into the economic impact of deer on England’s agriculture. Using these data and combining them with the results of DEFRA’s Agricultural Census (June 2002), biologist Charles Wilson estimated that deer cost English agriculture around £4.3 million (that’s about US$6.9m or €5m) per year – the range given was £1.1 million to £5.6 million. It seems that those farms growing cereal crops were hardest hit, with an estimated annual cost of £2.4 million (US$3.8m or €2.7m).

Shortly after Wilson published his estimate, a team of biologists -- led by York University biologist Piran White -- published their data on the Economic Impacts of Wild Deer in the East of England. In their report, the biologists estimated that deer cost the economy of East England between £7 million and in excess of £10 million (US$11m – 16m or €8m – 11.5m) per year; around £3.2m (US$5m or €3.6m) of this represents damage to agriculture in the region and most of this to cereals.

Red stag browsing treeSo, what sort of problems do deer pose to agriculture? Well, predominantly, they eat crops; they are particularly partial to cereal crops such as wheat and maize. Deer will also eat root crops -- especially carrots and potatoes -- and fruits, although this seems to be less common than damage to cereals. The types of crops damaged seem to depend on the species in the vicinity and how close they are planted to woodland. Crop damage varies substantially in accordance with both location and season, but there are some general trends that occur in the literature. Roe deer seem most partial to root crops and fruits and are typically responsible for most such damage, although Red deer will also indulge should the opportunity arise. In their analysis of East England, White and his colleagues found that Fallow and Roe were the species most commonly implicated with damage to cereal crops and, overall, two-thirds of damage to agricultural crops was attributable to these two species. The biologists also reported that deer damage to agricultural crops tended to be concentrated close to (i.e. within about 1km, or just under ¾ mile) of woodland edges. In conjunction with crops that are eaten, there is often associated damage from trampling of crops as the deer move around the plots.

Crop damage is associated with deer density as much as it is with species. In their report, White and his team wrote: “The medium threshold landscape densities (deer per km2) at a 10-km square scale for deer damage to agriculture are estimated to be as follows: fallow, 0.437; muntjac, 1.838; red, 0.231; roe, 0.971.” So, for example, damage to crops is more likely to result if there is more than one fallow deer per 2.5 square kilometres.

The link between deer and agriculture isn’t confined to crop damage – they are also known to compete with domestic livestock for grazing and there have been some instances where deer have been hosts for diseases that can be passed to livestock. Red deer, for example, are known to compete with sheep for grazing resources, while they are complimentary grazers with cattle. The tooth arrangement and jaw structure of a grazer dictates the height of the grass it can eat. Cattle have a large bite and crop the grass to a height just right for deer. Unfortunately, deer and sheep have a roughly equal bite and so the two compete for the same length of grass. Deer have also been implicated in the spread of the tick Ixodes ricinus, which in turn is the main host for the bacteria Borrelia burgdorferi that causes Lyme disease. Deer are known to be susceptible to the Aphtae epizooticae (Foot and Mouth) virus and there is also some evidence that deer can transmit the Mycobacterium bovis bacteria responsible for bovine tuberculosis, albeit that the risk is considered low. It has also been suggested that deer could aid the spread of bluetongue – the disease is caused by the Orbvirus retrovirus, which is spread by Culicoides midges. According to the Parliamentary Office of Science and Technology (POST), deer can act as a “reservoir in which the virus can over-winter, and in which new viral strains can establish”.

Deer can also pose problems for forestry. In their “POSTnote” on wild deer, the POST writes: “Deer can cause significant damage to forestry by reducing tree regeneration, browsing saplings, and bark stripping”. Bark stripping tends to be confined to the antler cleaning and rutting seasons, although deer will strip and eat bark (especially during the winter) for various reasons. In some cases, bark may constitute a large proportion of the diet. A review of bark stripping behaviour in deer across Europe published in 2006 found that in areas where winters were severe (i.e. heavy snow), bark contributed more than 10% to the diet of Red deer. The study also uncovered highly variable rates of bark stripping, ranging from none to 84% with “less damage in Scotland than in other European sites”. Nonetheless, the Forestry Commission for Scotland estimate that damage to forests caused by deer costs them around £4.5m every year. Fences can be erected around plantations, although these yield variable results. Young saplings can also be encased in a Tuley tube to protect it during the crucial early growth stage – these tubes are now common in our countryside (some estimates suggest there may be 70 million in the UK) and are named after their inventor, Forestry Commission biologist Graham Tuley. In deer parks, it is now common practice to see wooden or metal fences around trees to protect them from the deer. (Back to Menu)

Decline in Bird and Plant Species: Deer are grazers and as such affect vegetation in the habitats where they feed. Given that both Red and Roe are part of our native fauna (i.e. have been here since the last glacial retreat) and that Fallow have been in the UK for the last thousand years (or more), there is a strong argument that they have evolved with their habitats. However, we have recently seen a steep rise in deer numbers -- one recent estimate put the number at around two million and some have suggested that number could double by next year -- and many biologists think that this is putting increased pressure on many of our most valuable ecosystems. The government’s POSTnote points out that “Lowland ancient woodland, upland heath and blanket bog can suffer particularly from deer over-grazing, excessive browsing and trampling” and notes how “4,000 hectares [almost 10,000 acres] (about 4%) of woodland with SSSI [Site of Special Scientific Interest] status is currently in ‘unfavourable’ condition due to deer impacts”.

Any change to an ecosystem invariably has consequences for its inhabitants. There have been many studies looking at the impact deer may have on bird populations, but the results are contentious – some have found a link between deer removing understorey vegetation and a decline in ground-nesting birds, while others have failed to link the two.  Nonetheless, high deer densities do have a demonstrable impact on both the composition and structure of plants in a given habitat and this change has been linked to declines in various invertebrate species.  Logically, given that invertebrates are a staple food source for birds (especially songbirds), a decline in invertebrate numbers is likely to have an adverse impact on bird numbers.

A study looking at the impact of deer on songbird populations on the archipelago of Haida Gwaii (off the British Columbian coast) published in 2005 concluded that “deer [in this case, Black-tailed deer, Odocoileus hemionus sitkensis] overabundance results in a decrease in songbird habitat quality through decreased food resources and nest site quality and may explain part of the continental-scale decreases in songbird populations”. Closer to home, the situation is considered similar. According to the Forestry Commission for England’s Woodland Improvement Grant 80 (March 2009) appraisal, the decline of the woodcock (Scolopax rusticola) in the Yorkshire and Humber region can be at least partly attributable to “deer/sheep browsing leading to loss of shrub layer”. There is also the question of what impact these changes to vegetation structure and invertebrate communities has on small mammal populations, but there are very few data on this.

White-tailed DeerFortunately, the situation is not a hopeless one and there are measures that can be taken. The exclusion of deer from areas of wood and grassland by fencing can be highly effective, although it is also costly and deer are good jumpers and can be rather determined in their efforts to regain entry. Similarly, culling can be implemented in order to reduce the local deer population (arguably there is currently a desperate lack of professional deer stalkers in the UK) and, if the meat is sold as venison, this can help offset the costs of deer management.

It should not be assumed that all deer-related impacts on woodlands are problematic. By removing shrubby growth and bramble, the deer open up the forest floor and allow colonisation to species that are otherwise rapidly out-competed. Similarly, deer can also help to disperse plants and may play a key role in the regeneration of fragmented woodlands. At the 12th Annual Conference of the International Association for Landscape Ecology, held in Cirencester (Cotswolds, UK) during June 2004, Forestry Commission ecologist Amy Eycott and two colleagues presented data on how deer disperse plant seeds in their scat. Eycott and her co-workers report that large-bodied grazing deer had the greatest number of seeds and highest number of seed species in their pellets. Studies in America have found a similar situation with White-tailed deer (Odocoileus virginianus - right). (Back to Menu)

Damage to People, Property and Pets: One only needs to type the words “deer attack” into the video search of YouTube to see evidence that deer sometimes ‘lose patience’ with humans. In the majority of cases, this is just a short charge because the person with the video camera gets a little too close, or does something stupid. There are a number of cases, however, where the aggression is serious and the unfortunate victim ends up in hospital, or worse.

Perhaps the most famous fatal encounter with a deer was that of King William II’s older brother Richard, the Duke of Bernay, who (at the age of about 27) was killed by a stag while on a hunting trip in the New Forest sometime around 1081. More recently, in September 2002, a hillwalker underwent surgery after being gored by a Reindeer (Rangifer tarandus) in Scotland’s Cairngorm Mountains. Two years later, a deer farmer in North Yorkshire was killed by one of his rutting stags.  Indeed, in his fascinating Kia: A Study of Red Deer, Ian Alcock wrote of his apprehension at keeping a stag, as they are highly aggressive and unpredictable during the rutting season. I have heard similar stories from people who have surprised (or should that be, been surprised by) stags while out walking – one keen fisherman from West Sussex described to a friend of mine how he had to climb on to the roof of his car during a confrontation with a deer in St Leonard’s Forest. Ultimately, the combination of powerful weapons in the form of antlers and the flooding of the body with testosterone is a dangerous combination for bystanders.

Situations are sometimes made worse by the unacceptable risks some people are willing to take to get a decent view of the rut. According to keepers in one area of the New Forest, the Red deer rut is becoming an increasingly dangerous time as photographers place themselves too close to the action – in some cases, between two challenging stags! In the case of the New Forest Red deer rut, the keepers have noticed a change in the deer’s behaviour and distribution patterns. It seems that the increased disturbance is causing deer to move out of the region, increasing their susceptibility to traffic collisions and causing them to move into Sika (Cervus nippon) 'territory', where they are currently shot on sight in a bid to prevent hybridization. It is not unknown for people, even those familiar with being in the company of deer, to get injured trying to get shots of rutting deer. In the bio section of his Sett on the Heath DVD, wildlife cameraman Rodney Goodhand tells how he was hospitalized after being charged by a Sika stag while filming at Arne in Dorset – the deer cut open his hand and injured his thigh. I have no doubt that Mr Goodhand was being sensible in his actions so this just goes to show that even careful observers are not immune to the threat of injury.

In terms of damage to property, deer are known to eat garden flowers and vegetables and may cause damage while doing this. Similarly, in the case of the unlucky fisherman referred to earlier, I am led to believe his car had a few scratches on it. Deer have also been implicated in attacks on dogs. In the majority of cases, injury has occurred when the dog chased the deer. Such cases tend to be most commonly associated with Muntjac (Muntiacus reevesi), which seem to have a habit of abruptly stopping during the pursuit and crouching down with their head tucked under their chest (exposing their sharp, pointed antlers). A swift upward movement of the head can lead to the near disemboweling of an over-enthusiastic dog. I have read some accounts to suggest that dogs have been killed in this manner before, although I have not read any firsthand accounts. I should point out that the chance of a dog being injured by a deer is slight -- especially when under its owner’s control -- and that deer (especially fawns/kids) are at far greater risk from dogs. (Back to Menu)

Traffic Collisions: Road traffic accidents involving deer seem to be a growing problem. According to a study published in October 2001 by the Deer Commission for Scotland, some 300 people are killed and 30,000 injured in collisions with hoofed game across Europe each year. In the UK, it is estimated that there are about 200 accidents involving deer everyday and 20 people are killed per year. In 2007, the Deer Initiative in conjunction with the Highways Agency published their Deer On Our Roads survey results. Between January and December 2005, there were more than 30,500 reports of deer-vehicle collisions (DVCs) in Britain, of which nearly 25,000 (82%) occurred in England. Disturbingly, the report concludes that these records make up only a small percentage (perhaps only 20%) of the actual DVCs nationwide and that the true figure for Britain may exceed 74,000! Indeed, in his Fauna Brittanica, Hart-Davis points out that it is almost impossible to quantify the total number of deer killed on the roads, because many disappear in the boots of cars! In England, the report found that Fallow were involved in 40% of the DVCs, with Roe hit in 32% of cases and Muntjac in 25% - Red, Sika and Chinese Water deer contributed less than 3% combined. In an article to Surveyor magazine during October of 2004, Alexandra Wilson and Jochen Langbein note that “The annual cost of car repairs alone, over and above losses associated with human injury costs from such [DVC] incidents, is estimated to exceed £11m [US$17.5m or €12.6m]”.

Fallow deer crossing road
Deer are very susceptible to being hit by vehicles, particularly females because they tend to aggregate in matriarchal groups and when the leader decides to cross, the others follow. Here a small group of Fallow does (Dama dama) cross a road in the New Forest after being frightened by a dog walker.

Wild Mammals Crossing road signAs might be expected, there are certain locations and conditions under which a collision with a deer is more likely to occur. The Deer Initiative’s study found that DVCs were most common in Southern England and, between 2003 and 2005, there were more than 75 per 5km (~ 3.5 miles) stretch of “hotspot” road in this region – some of the worst places for DVCs included Southampton and Portsmouth. Collisions with Fallow and Red deer were more likely to happen between October and January and the peak time for DVCs was from early evening (about 6pm) until midnight and then again corresponding to the morning rush-hour (6am to 9am). A study published in the German journal Tierarztliche Umschau found that more accidents involving Roe deer in North-west Germany occurred on dull days, with an increase in the number of such days making December one of the worst months for road traffic accidents involving deer.

Much work has been done with the goal of finding methods of reducing the number of DVCs worldwide – these have included reflective posts by the roadside, acoustic alarms triggered by headlights and ultrasonic whistles attached to cars. The results have been mixed and, in the case of some designs of deer whistles, there is debate as to how effective they are likely to be.

Cars aside, crop mowers represent an important mortality factor for some deer species. A study by Anders Jarnemo, published in the journal Wildlife Biology, looked at the mortality rates of Roe kids on intensively farmed land in Sweden. Jarnemo, a biologist at the Swedish University of Agricultural Science, found that between 1997 and 1999 some 25% to 44% of the yearly recruitment of Roe deer was killed by mowers. Susceptibility continued until the kids were at least one month old. Jarnemo notes that putting a black plastic sack on a two metre (6ft) pole into a field set to be mown resulted in the mothers moving 21 out of the 22 kids bedded there by the second day, thereby minimizing mortality. (Photo: In Britain, the road sign alerting drivers to wild animals crossing depicts a running Red deer stag.) (Back to Menu)

Art and Cultural Subject: Deer have long been part of human art and culture, from coins and stamps to art work and poetry. In mythology, deer have been considered determined snake killers and, according to Norma Chapman in her 1991 book Deer, Fallow were introduced to the Greek island of Rhodes by the Knights of the Order of St. John of Jerusalem in a bid to ‘stamp out’ the snakes. The subject of deer in human art and culture is covered in great depth by G. Kenneth Whitehead in his 1993 The Whitehead Encyclopedia of Deer; that which follows is based heavily on the information presented by the late Whitehead, who was undoubtedly one of the most inspiring figures the pursuit of deer stalking has ever known.

Perhaps the most common use of deer in our western culture is in their inclusion into family crests and coats of arms – that is to say, deer as a feature of heraldry. In his encyclopaedia, Whitehead lists just under 1,300 (I counted 1,285) family names with an associated crest featuring a deer. It seems that such crests can be divided into 11 groups, running from A to K, in accordance with the type of image they contain (i.e. the species, the whole or partial animal, what it’s doing etc.). By far the most common class is I (those showing a stag or buck head), while the least common seems to be C (showing a stag or buck “at gaze”), with only 12 associated families. Of course, deer don’t only show up in family crests – they also feature in corporate and military crests. Whitehead follows George Briggs’ earlier (1971) work on deer in Civic and Corporate Heraldry and lists, again by my count, 127 councils, schools/universities, societies and companies that include deer in their crests. These include Oxford University’s Jesus College and the University of Southampton. Whitehead goes on to list 10 military units and nine Scottish clans who feature (or have featured) deer on their crests. Not only do some towns and cities bear deer in their crests, some have names relating to deer. In an unpublished study of place names, Sarah Beswick lists more than 250 that contain reference to deer. These include places like Hindhead in Surrey, Buck Hill in Essex and Rogate in Hampshire. Added to place names are a considerable number of pubs with “hart”, “stag” and “buck” in the name.

Buckley Family CrestMcCartney Family CrestMcDaid Family Crest
Deer are featured in many family, corporate, governmental and educational coats of arms. In the above graphics depict the coat of arms for the Buckley, McCartney and McDaid families and are taken from Free Coats of Arms.

Deer appear in much of our art and literature; perhaps the oldest of these are the deer featuring in Stone Age cave paintings in southern Europe. Much of the artwork has been featured on postage stamps and in the study of philately, there are numerous occurrences of cervids. Whitehead provides detailed lists of deer appearing on stamps worldwide and it seems that Red deer have featured on the stamps of at least 41 countries, including the £1 stamp released in Britain during 1987 to commemorate the 150th Anniversary of Queen Victoria’s ascension. Roe deer have featured on the stamps of at least 28 countries, Fallow 16 countries, Sika 14 countries, and Muntjac have appeared on stamps in at least two countries. Stamps aside, deer have been the inspiration for a great many painters. Perhaps the most famous deer portrait was one of a series of paintings commissioned from the English painter Sir Edward Landseer in 1851 by the British monarchy to hang in London’s Westminster Palace. The Victorian oil painting depicts a majestic 12 point Red stag standing on a Scottish mountainside and is entitled “The Monarch of the Glen”. Stags are often grouped according to the number of branches to their antlers and the one featured in Landseer’s painting was a “Royal” (12 point) stag – a “Monarch”, in terms of antler branches at least, has 16 or more points. Landseer was far from the only painter to feature deer in his work – Mr Whitehead lists 118!

Statue of Red StagImages of deer feature heavily in ceramics, including plates, vases and statues and there are numerous references to deer in decorative glassware. Cervids (either depicted just as a stag’s head, or the entire animal) are also found on metal buttons -- typically made of brass with a thin gold wash -- that were apparently popular among 19th Century sportsmen; according to Whitehead’s account, these are known as “Gilts”. Deer have also been depicted on currency and, although there are no English coins currently in circulation with deer on them, Whitehead lists 13 countries that have, at some point, had coins in circulation with images of deer on them; in the same section, he also lists 11 countries that have depicted deer on their bank notes, including the 500 rupiah bank note of Indonesia. The oldest reference to a coin bearing the inscription of a deer I have come across is a Greek coin from the ancient city of Ephesus, dating back to the 4th Century B.C.

Deer hold a deep-rooted place in our popular culture – few cannot be familiar with Father Christmas and his nine flying reindeer. In his classic 1950 children’s novel, The Lion, The Witch and The Wardrobe, Clive Staples (C.S.) Lewis included a white stag that grants wishes to whoever catches it. There is an “imperial” (12 point) stag in the 2006 British film The Queen, starring Dame Helen Mirren and, in Colin Dann’s charming story The Animals of Farthing Wood, the ‘king’ of White Deer Park nature reserve is the Great White Stag that, in the cartoon adaptation, was voiced by British stage actor Ronald Moodnick.

Finally, deer also have their place in more oneiric and mystical matters. Dreams can be frustratingly difficult to interpret and, as such, different interpreters will have various interpretations of the meaning, based on the dreamer’s personal circumstances. Some suggest that, in dreams, deer symbolise feminine qualities (i.e. grace, tenderness and beauty) as well as independence and virility. Dreaming of killing a deer is said to represent an attempt to suppress feminine qualities. Others, however, see deer as representing strong friendships for the young and a peaceful life for the married. Many cultures hold deer as sacred animals and consider them to possess mystical powers.  Some Native Americans consider the deer to be the vessel of the soul and that a dead or dying deer foretells of hard times to come. Many also sought less obvious bits of deer for their reputed healing properties.  The stony concretions (called “Bezoar stones”) that occasionally form in the stomachs of ruminants, including deer, were highly prized because they were considered a universal antidote to any poison. Some sources suggest that these stones were named after the Pampas deer (Ozotoceros bezoarticus), while others consider the name to be derived from the Persian word for “protection from poison”. Regardless, there is little scientific evidence that these ‘stones’ do much to neutralise poisons, although there is some evidence that some of them can bind arsenic under certain conditions. (Back to Menu)

New Forest Fallow buckFeeding Interactions: In general, feeding of wild deer is not a popular pastime in the UK and this is probably to their favour. Wildlife services in the USA have considerable problems with landowners putting out food for deer during the winter months. The problem revolves around the fact that deer are ruminants. As mentioned above (see Food & Feeding), deer share a syntrophic relationship with numerous species of microbe that breakdown the food they eat. Moreover, the species of bacteria, protozoa, fungi or archea present is related to the deer’s diet. Thus, deer feeding on grass and saplings have different species of bacteria to those feeding on bark and heather. This presents a problem when putting out food for them.

In Montana, for example, people put out corn and hay for deer over the winter months. Unfortunately, the deer -- which have been grazing in spring pastures -- don’t have the gut microorganisms necessary to digest this food. However, deer are understandably unaware of their digestive predicament and will usually eat the food regardless. Consequently, it is not unknown for deer to starve to death with full stomachs.  Furthermore, 'word' of feed troughs spread rapidly in the deer community, and a single trough can attract great numbers of deer. This means that the cost of feeding the deer begins to grow rapidly, especially considering that they need about 1.5 kg (3.5 lbs) of decent vegetation per day. According to the Montana State University, the presence of a feeding trough can also cause deer to become abnormally competitive (striking each other with hooves) and young deer, which are often in greatest need of the food, are kept away by larger individuals.

Despite all the problems that deer can cause us, it should be remembered that in many cases they provide a valuable source of income at a local scale. The deer rut is now a big draw for wildlife enthusiasts and with correct management and regulation this could be safely enjoyed by all. I don’t have any statistics on the subject (I’m not even sure that any exist), but I know from experience that hotels and campsites in the New Forest start filling up with visitors -- bringing valuable revenue to the local towns and villages -- around the time of the Red and Fallow ruts and I am sure that the situation is repeated elsewhere in the UK during this season. Even if you don’t make an effort to see the deer rut, I find even a fleeting glimpse of a deer while walking in the woods an exhilarating experience and I know many others feel the same. (Back to Menu)

Internal Links (for external, please see Links):

 -- Red Deer (Cervus elaphus)
 -- Roe Deer (Capreolus capreolus)
 -- Fallow Deer (Dama dama)
 -- Sika Deer (Cervus nippon)
 -- Muntjac Deer (Muntiacus reevesi)
Questions and Answers (Q/A):

What are antlers and what purpose do they serve?
What are TB and CWD and how do they affect deer?
Is it okay for me to feed wildlife?

Please be advised that the main deer profiles are currently in production and they will take time to complete. The species profiles will be added in the order they appear in the list above and, until the profile goes live, the above links will take you to the species' Speed Read profile.

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