FOXES

-- What are mange and rabies?
-- How can I protect my pets from attack by foxes?
-- What do you know about losing a pet?
-- Why shouldn’t I feed foxes (and animals in general) chocolate?
-- Why does my dog seem to have a penchant for rolling in fox scat?
-- Are foxes native to Britain?
-- Does surplus killing represent a "waste" of energy & resources for a fox?
-- Are there exceptions to the 'Scatter Cache Rule' for foxes & what are the benefits of Scatter Caching?
-- Are foxes colour blind?
-- Can I keep a fox as a pet?

Q: What are Mange and Rabies?

A: There are several different types of mange, but the most common found in foxes is sarcoptic mange.   Sarcoptic mange is a skin disease caused by a small (2 to 4 mm / less than ¼ of an inch) parasitic mite (Sarcoptes scabiei var. vulpes), several thousand of which may burrow into a single square-centimetre (about one-sixth of a square inch) of skin.   In humans, S. scabiei causes the condition commonly referred to as "scabies" and foxes have been known to infect the occasional human.   Female mites burrow into the skin where they may live for as long as two months.   Excretions from the mite harden to from a crust on the skin, leading to lacerations, hair loss and possible secondary bacterial infections.   Conjunctivitus and changes in behaviour (the infected fox becomes less and less active) are also common.      So intense is the irritation caused by this mite, that foxes are reputed to have gnawn off appendages!   Weight loss and organ damage are sometimes evident and, if left untreated, death follows in four to six months.   Indeed, the impact of mange on fox populations may be dramatic; the outbreak in 1994 succeeded in wiping out 95% of Bristol's fox population in only two years.

Foxes undergoing their summer moult are sometimes mistaken for those suffering from mange, because the infection starts from the hind quarters and spreads forward; infected foxes often have very bedraggled looking hips and tails.   The Sarcoptes scabiei parasite (above, right) is conventionally treated with Ivermectin, although sulphur with arsenicum is a common homeopathic alternative.   According to an article in the BBC Wildlife Magazine during July 2001, severely infected foxes may be taken into captivity for treatment, although it seems that they may return to find their territory has been taken over by another fox within a few days.

Rabies is a very different disease, with the potential to affect all mammals.   Rabies is an acutely infectious viral disease of the central nervous system (CNS), which is transmitted in the saliva of infected animals (especially dogs) and was epidemic in the UK until 1903, when it was eradicated through the control of stray dogs.   Rabies made a brief return to the UK (and specifically Plymouth) in 1918 when servicemen brought back rabid dogs, although it was eliminated in1922 following 322 confirmed cases.   The disease is characterized by excessive salivation, an aversion to water, convulsions and paralysis.

Rabies is caused by a rhabdovirus -- viruses of the family Rhabdoviridae, which are surrounded by a fatty membrane and are bullet-shaped -- often present in the salivary glands of infected animals and is most frequently transferred in a bite.   The most common genera of rhabdovirus involved in rabies infections are Lyssavirus.   After infection, the virus becomes established in the CNS, moving from the bite to the brain (via nerve tissue).   The disease usually develops within four to six weeks after being bitten, although incubation may be anywhere from ten days to eight months.   The symptoms begin with excitation of the CNS, leading to increased irritability and 'viciousness'.   Death usually comes about three days after the symptoms, and it is almost always fatal in humans – there is only one report, from 1971, of a man recovering from rabies.   A serum treatment for rabies was introduced in 1899, which can be effective if admitted soon enough after infection; the Human Diploid-Cell Vaccine (HDCV) and Rabies Vaccine Adsorbed (RVA) offer the most effective protection from the disease.

The World Health Organization (WHO) estimate that between 40,000 and 70,000 people die of rabies each year, and as many as 10 million receive post-exposure treatment annually.   The Center for Disease Control and Prevention in America report that about 25,000 people (most of which are children) die of rabies each year - the difference between the two estimates probably reflects the number actually reported to authorities.   In November 2002 a bat handler was admitted to Dundee Hospital in Scotland suffering from rabies contracted through a bat bite; this was the first case of wildlife rabies in Britain since 1902 and proved fatal.   Studies on the bat (a Daubenton’s Bat, Myotis daubentonii) by Department of the Environment Food and Rural Affairs (DEFRA, formally MAFF) found European Bat Lyssavirus II present in its saliva.   Animals known to carry rabies include dogs, cats, cattle, bats, skunks, raccoons, foxes and possibly rodents.

Rabies is not a new disease; according to Stephen Harris & Phil Bakers book Urban Foxes, our earliest records of rabies come from the Babylonian law-makers, who -- in 2300 BC -- imposed heavy fines on owners of rabid dogs who did not confine their pets.   The current epidemic in Europe originated in Poland during 1939 and has spread west.   Most of the infected animals are wild and 90% of them are foxes.   Various methods have been tested to try and halt the spread of the disease.   Vaccination of foxes against rabies -- through air drops of food containing the safe virus -- succeeded in eradicating rabies throughout much of western Europe by the end of the 20th Century, although the disease still persists in Coratia, Czech Republic, Hungary, Poland and Slovakia. (Back to Menu)

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Q: How can I protect my pets from attack by foxes?

A: Foxes don’t normally attack domestic pets, and accounts of dogs or cats being attacked by foxes are rare.   Indeed, in one instance a fox was documented to raise a litter of young under the floorboards of a house with a cat and a dog.   The fox would regularly walk past the cat and dog on her way to and from the disused room, and neither of the pets seemed unduly concerned or attempted to intervene.   However, foxes are wild predators and do occasionally attack and kill smaller livestock (e.g. chickens, ducks, rabbits, guinea pigs etc.).   In most cases, attacks are on pets that aren't securely housed and, consequently, there are certain precautions that you can take to reduce the likelihood that a fox could gain access to your pets.

Ducks, geese, chickens, rabbits and guinea pigs should be put away at night in secure hutches or cages.   When thinking about what constitutes a “secure” compound, it is exceedingly important not to underestimate how intelligent foxes are.   Hutches with simple twist closures are usually insufficient to prevent a fox gaining access, and a small bolt on the door should be considered essential.   Pets should be shut away at twilight.   Most fowl will begin to settle down for the night at twilight, and it takes only a couple of days of being ushered into a hutch for the night for them to realize this is where they should sleep.

Foxes are opportunistic predators and will not pass up the chance of an easy meal.   Securing a flock of chickens for the night is more involved than is securing a pet rabbit or duck.   However, it is nonetheless possible to provide your chickens with "fox-proof" housing – in their book Ducks and Geese at Home, Michael and Victoria Roberts present three practical alternatives to sitting outside the chicken coup all night with a shotgun.   The first -- and most elaborate -- method involves building a 2m (6ft) high mesh fence around the chickens, with electric wires running around the perimeter of the fence at the top and bottom.   The second method involves a 2m fence with an overhang at the top, slanted out at about 45^o and wire at the base of the fence running out to about 60cm (2ft).   The third method is the same as the second, but with a 1m (just over 3ft) plateau at the top to stop the fox climbing up and over the fence.   It seems that the most important factor to remember is that foxes will dig as well as climb, and so netting should be dug into the ground or laid flat on the ground around the fence in order to prevent the fox from digging its way under.

Perhaps the two most important points to remember to constructing (or purchasing) a house for your livestock is that chicken wire is not sufficiently strong to keep a fox out - foxes can bite through it without much of a problem.   Similarly, there should be a base to the house (wooden, metal, paving slabs, etc.) to prevent the fox from digging under the fence and a cover on top to prevent the fox climbing over.   So, if your hutch/hen house has a roof and a floor, is composed of tough wire and has bolts on the doors it can be considered fox-proof.   (Back to Menu)

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Q: It’s all very well for you to sit at your computer and tell people that foxes only kill pets to feed themselves and don’t kill for sport.   What do you know about the grief associated with losing a pet to a fox?

A: Until a few years ago, nothing!   As I sit and write this, my mind drifts back to the events of Thursday 6^th November 2003 and the surprise that I recall feeling upon getting up to investigate the quacking of our two pet "Call" ducks.   For those of you who are familiar with the 9 standardized and half-dozen or more non-standardized types of Call duck listed by the British Wildfowl Association in 1999, one was a "Grey" or "Mallard" and the other was a "Bibbed" duck.  

Anyhow, looking out of my dining room window, I saw the Bibbed duck (named Flick - the brown duck in the photo on the left) lying almost motionless on the netting of our fishpond, pinned down by an adolescent fox.   Shouting “Oh no you don’t!” or some such -- admittedly slightly more explicit -- harangue, I shot through the kitchen and flew out of the back door shouting at the top of my lungs.   I had hoped that shouting at the fox would cause it to drop the duck and flee – I was wrong; it did indeed flee, although much to my increasing despair took its quarry with it.   We have a fence and gazebo-type structure separating our garden roughly in half – “A ha” thought I as I chased the fox up the garden, “It’ll have to drop the duck to get under the fence”.    Wrong again!   The fox slipped under the fence -- a gap of only some 12 ½ cm (5 in) -- with the duck still clasped firmly in its jaws.   It then went around our shed and over the back garden wall, with me in hot pursuit, screaming for all I was worth!

Where I used to live, the back gardens of each row of houses back on to each other, with a narrow gap of about 60 cm (about 2ft) separating the two opposing gardens.   This area was overgrown, with brambles, discarded glass, bricks, paving slabs and the odd tree interspersed for good measure.   It was along this rugged ‘alleyway’ that the fox took our duck.   I screeched like an opera singer with an appendage caught in a car door, and the fox dropped the duck into a small crevice under some steel pipes.   Looking desperately, I spotted Flick floundering in this pit and chirping in a quiet and rhythmic manner (signifying stress).    Now, had I been thinking clearly I would’ve gone back into the house, got the telescopic loppers and hacked my way through the undergrowth something akin to the great Scottish Missionary Dr David Livingstone.   However, I was concerned that the fox may return in my absence, and I was damned if I was going to just leave Flick there to die from his injuries. 

Ergo, I clambered -- rather ungracefully it has to be said -- on to the wall and down into the undergrowth.   I clambered across broken bricks and paving slabs, being reasonably careful to avoid the glass.   Squeezing through the bifurcated trunk of a smallish tree, I found myself entangled in branches and bramble.   All this time I was talking at Flick to try and reassure him.   I finally fought my way through the brambles, and was just able to lift the steel pipes off him.   Picking him up, and holding him close to my chest I began my travels back to the familiarity of my garden, talking to him all the way.   We made it back, and in the light of day I could see that he was bleeding quite badly.   I tore a handkerchief from the washing line as I scurried past and used it to cover his head, to reduce stress (thanks for that tip, Animal Hospital!).   I put him in his hutch and raced in doors to phone the vet and get him an appointment. 

At the vet's he was examined, and we found a large cut about 3cm (about 1 ½ in) long and about 2cm (1 in) deep.   The fox’s teeth had cut clean through his skin and into his breast muscle.   Fortunately, it had not punctured his air sac (lungs) or he would’ve died almost immediately.   We left him at the vet, returning a couple of hours later to pick up our newly sewn-up duck.  Upon collecting him we were told that, during the surgery ,they had found not one, but four punctures, all of about the same size and depth – one from each of the fox's canines.   We put him in his hutch, and he was confined for about a week.   The first night was tense and it was with serious trepidation that we looked in the hutch the following morning – to our relief we found Flick still in the land of the living.   It was quite likely that the trauma of the situation could have killed him that night.   We hoped that, over the next fortnight, he would make a satisfactory recovery and we did everything within our power to aid and expedite the situation.   Sadly, upon our return to the vet a week later, Flick had to be put-to-sleep – he hadn’t eaten anything over that week and was shaking and chattering quietly.   The vet considered that he might have received brain damage during the incident.

In the long run, I suppose it would’ve been sensible to let the fox take Flick.   However, at the time I was not thinking clearly and acted on impulse.   Immediately after we lost Flick, his brother (Flash) seemed distressed at the loss of his sibling and became aggressive.   Since Flick’s departure, we have got Flash a playmate (called Storm) and the two follow each other around like they’re chained together! Although Flash is still aggressive towards my Mum (and it seems, women in general), he has improved and seems a much happier duck.   We have also made some alterations to our garden now and have more control over where the ducks are allowed to wander – we have not seen sight or sound of the fox since, despite hearing that a family down our street lost a rabbit recently. 

So, has this changed my perception of foxes?   Do I have a compelling urge to don a red coat and join the group affectionately referred to by The Guardian as the “Tally-Ho Brigade”?   No, not at all.   As a rational person, I see that the fox was only doing what it has evolved to do: feed itself and its family.   However painful the situation was for Flick and our family (both emotionally and physically – I have the scars and rashes on my hands, arms, shoulders and face to prove I’ve ‘been there, done that’!), I don’t blame the fox one bit.   I will concede that I was gob-smacked that this attack happened at 1.30pm in the afternoon -- the irony of it being lunchtime is not completely lost on me -- during broad daylight, when I had hitherto considered foxes nocturnal or crepuscular (i.e. dawn and dusk) predators.   However, you learn something new everyday. 

Intriguingly, none of my family blames the fox either, and I find this almost as refreshing as those people who suffer terrible mutilation at the jaws of a shark and then campaign for the protection of these magnificent fish.   Getting scratched and stung whilst attempting to rescue a small duck from the dinner table of a fox is one thing, but being hauled from the water by a lifeguard and waking up in the hospital missing an appendage must be harrowing.   Moreover, for these people to maintain the opinion that ‘well, the shark was just doing what it supposed to be doing and our two worlds just, kinda collided!’ is a type of clarity and fortitude that I could only hope to possess.   (Back to Menu)

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Q: Why shouldn’t I feed foxes (and dogs in general) chocolate?

A: I was an avid watcher of the BBC’s Animal Hospital program, and almost every week the vets would see a dog that had developed a sweet-tooth and helped itself to its owner’s secret stash of chocolate.   However, the problem that dogs have with chocolate is a serious one, and revolves around how they digest a specific ingredient; Theobromine.   Theobromine is part of a family of chemicals called methylxanthines (nitrogenous organic molecules), related to caffeine.   Milk chocolate contains anywhere up to five grams (average is about 2 g) per kilogram of theobromine, while dark chocolate can have as much as ten grams.   Humans take, on average, between four and six hours to metabolise ingested theobromine, while dogs take about 20 hours.   According to the American Society for the Prevention of Cruelty to Animals, theobromine is toxic to dogs at 150 to 200 mg per kilogram body weight, although problems have been noticed at levels as low as 20 mg kg^-1.

In dogs, methylxanthines are absorbed by the intestines after which they are carried -- via the hepatic portal vein -- to the liver.   Some of the methylxanthines are successfully excreted by the liver, but many make it into the inferior vena cava (the vessel that takes the blood into the right-hand side of the heart) where it travels through the pulmonary (lung) circulation and into the main circulatory system.   The situation is compounded by the fact that some of the methylxanthine by-products excreted by the liver into the bile ducts can be converted back into methylxanthines and reabsorbed by the small intestine.   Ultimately, this means that humans can effectively breakdown and excrete theobromine, while dogs cannot.

Theobromine causes excitation of the central nervous system, while also stimulating the heart and increasing blood pressure.   Signs of theobromine poisoning in animals usually include excitement (i.e. nervousness and trembling), vomiting and/or diarrhoea, excessive thirst, muscle spasms and possibly seizures.   Coma and death (resulting from alteration of normal heart rhythm) are rare but possible outcomes.   According to vet Janet Crosby, if caught in time, theobromine poisoning can be treated with IV fluids, emetics (vomit-inducers), activated charcoal, anti-seizure medications and cardiac medications (see Links).   It is worth remembering that it is not only dogs that are susceptible to chocolate poisoning, most animals are – cats, rats and mice are all well documented to suffer as a result of eating chocolate.   (Back to Menu)

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Q: Why does my dog seem to have a penchant for rolling in fox’s dung?

A: This -- sometimes infuriating -- behaviour probably stems back to your pet pooch’s wild descendants: wolves.   To illustrate this, let’s say a wolf leaves the pack and ventures off on its own to forage or explore a territory.   On its wander, it comes across a novel smell (let’s say the fox excrement that all dog owners dread!).   The best way to share this 'interesting' smell with the other members of its pack (without the aid of a poop-scoop bag) is to roll in the substance from which the smell is emanating.   In this instance, the dog rolls in the fox scat, ensuring that it covers the sides of the face.  When it returns to its pack, the other wolves greet it by sniffing noses and will readily detect this novel scent.   Some canine behaviourists consider that a domestic dog rolling in dung may be a ‘hangover’ from their ancestors.   However, it is noteworthy (I shy away from the word “interesting” in this instance!) that my dog only seems prone to rolling in fox faeces – apparently opting to ignore the scat of other creatures (i.e. cows, deer and other domestic dogs), although she is apparently rather unique in this respect.   To my mind, larger canids might be more interested in other predator odours than the odours of prey - after all, foxes represent a competitor if you're a wolf.

Another theory is that by rubbing themselves in the scent of some other creature, they can mask their own scent and thus are less likely to be detected by a potential prey item, should they venture downwind of it.   This makes sense; deer likely run when they catch the scent of a wolf, but probably ignore foxes unless there are calves/fawns around.   At any rate, the jury is still out as to the precise reason for this particular behaviour, and the motive is probably associated with the specific odiferous substance and the relish with which the dog ‘applies’ it.   (Back to Menu)

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Q: On the BBC's Hunting TalkingPoint site, one participant said: "The fox is not 'our [Britain's] natural wildlife', it was introduced from France for the sport of the Normans and to help keep down the rabbits they had previously introduced here (another non-native species) and which had got out of control".   Is this true?

A: Conventionally, species “native” to a given country are regarded as those that have arrived since the last ice age, without human assistance.   Such species are also often referred to as being indigenous.   The last ice age to grip Britain ended some 15,000 years ago, and pre-glacial Britain had both rabbits and foxes.   As with many apparently off-the-cuff proclamations about foxes, the one given on the TalkingPoint site has elements of truth buried in an otherwise rather inaccurate statement.  

The first archaeological evidence for the Red fox (Vulpes vulpes) in Britain comes from the Wolstonian Glacial sediments in Warwickshire (a county in the midlands, just south-east of Birmingham).  The Wolstonian Glaciation started about 330,000 years ago and ended some 135,000 years before the present day (BP).   The same sediments also contain the first evidence for the Eurasian badger (Meles meles) in Britain.   During the Wolstonian, the landscape was probably mainly grasses and sedges with some dispersed woodland (this type of environment is called a “steppe”, by ecologists).

Following the retreat of ice from the last ice age (the oddly-named “Late Glacial”) some 15,000 years ago, many of the larger mammal species began to re-appear or extend their range northwards.   Among these mammals were the wolf (Canis lupis), Brown bear (Ursus arctos), Reindeer (Rangifer tarandus) and contrary to popular misconception, the Woolly mammoth (Mammuthus primigenius).   It was originally believed that the mammoth didn’t return to Britain after the maximum of (height of) the last glaciation.  However, the remains of four specimens (one adult and three juveniles) found in a kettle-hole (a pit full of sticky grey, sandy clay) in Shropshire have been radiocarbon-dated to 12,800 BP.

According to Derek Yalden’s fascinating book, The History of British Mammals, post-glacial remains of the Red fox have been found at several sites around Britain and suggest that this species re-appeared naturally around 10,000 years ago, as the ice of the Devensian Glaciation (70,000 to 10,000 BP) retreated.   Perhaps the best examples of post-glacial fox remains in the UK are at Gough’s Cave in Somerset, where Red fox remains have been found together with the remains of the Arctic fox (Vulpes lagopus).   Indeed, even if one were to approach the question from a purely literary perspective, foxes are mentioned in the Catholic texts of Bede and Alucin, both of which pre-date the arrival of the Normans.   I’m told that the Alucin actually admonished boys for spending their time digging foxes out of holes, rather than praying!

The question of whether rabbits (Oryctolagus cuniculus) are indigenous to Britain is somewhat more complicated.   Rabbit remains have been found dating back to the warm climate of the Cromerian Interglacial (750,000 to 350,000 BP).   However, it seems that rabbits didn’t make their own way back to Britain after the cessation of the last ice age.   Rather, it seems that rabbits may have been introduced by Roman settlers.   In 2005 archaeologists excavating a Roman settlement at Lynford in Norfolk found the remains of a 2,000 year old rabbit dinner, which may represent the earliest evidence of rabbits in post-glacial Britain.   Prior to this it had been considered that rabbits were re-introduced to Britain by the Normans during the 12^th Century (probably to provide food and fur).   Invariably, Norman settlers did bring their own rabbits, but it doesn't look like they were the first!   The precise date and source of the Norman introductions remain unclear, although the earliest definite mention of a rabbit warren is apparently from the Isles of Scilly in 1176.   Although rabbits originate from the western Mediterranean, the Norman Kingdom in Sicily may have provided a likely contact with -- as well as source of -- rabbits for Britain.   Thus, although rabbits are well known from pre-glacial Britain, they failed to reappear until the Normans brought them over some 900 years ago – this means that they cannot be considered truly indigenous to Britain.

Although the Red fox is a native species to Britain, this is not to say that the idea of foxes being introduced “from France for the sport of the Normans” is unfounded.   Indeed, there is considerable evidence to support the introduction of foxes from outside the UK when fox populations declined.   In his 1987 book, Running with the Fox, Prof. David MacDonald of Oxford University notes:

“Where numbers ran short [caused by hunting and a mange epidemic] foxes were bought and released (such ‘bagged’ foxes sold for 10 shillings [50p] at the Leadenhall Market [in London] in 1845) and included a brisk trade in imports from the Continent.”

In conclusion, we can say that foxes are part of Britain’s native fauna, although rabbits are not.   The Normans introduced rabbits to Britain and ‘re-stocked’ foxes when their numbers declined dramatically during the mid-to-late 1800s.  (Back to Menu)

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Q: Foxes are well known to kill more than they can eat at the time.   This behaviour often leads to foxes being branded “malicious” or “evil”, and merely the word “fox” is enough to bring out negative emotions in many livestock owners.   Why do foxes kill to excess when such activity seems to represent a waste of energy and resources for a wild animal?

A: The observation that foxes can do tremendous damage to domestic livestock is one of the pivotal arguments for the continuation of hunting by the pro-hunting lobby.   Unfortunately, there is no denying that foxes do kill livestock and sometimes do so to what appears to the casual human observer as “excess”.   The counter-argument to “well foxes kill all the chickens in the coop but only take a couple” is normally something along the lines of “that’s because the fox was disturbed during the caching process.  If you’d have slept through the ordeal, you would have come out to find your coup devoid of most of the hens”.   Unfortunately, there are no studies to support or refute this idea.   The basis for this argument is that foxes can only carry a single bird at any one time (making the process of caching slow) and the livestock owner usually comes to investigate the disturbance before the fox has had time to remove and store more than one or two birds.   Unfortunately, this is not necessarily accurate – there are many examples where foxes have killed two or three ducks, decapitating the birds, and have left the carcasses otherwise untouched.   It is instances such as these that have perpetuated the belief that “foxes kill for sport”, or that they kill because they “enjoy” killing.   Indeed, while following a fox hunting debate on an Internet discussion list recently, I read a post by a gentleman who considered that foxes only attacked our pets because they’re too small to attack us!

First let us deal with the idea that foxes get some pleasure out of killing, or kill for sport.   For a predator, killing is a pivotal part of their existence; it's not an exercise-based leisure activity.   Quite simply, to the exclusion of scavenging (which is highly unpredictable), if they don't kill something else they starve to death.   At the same time, it seems reasonable to assume that an animal wouldn't perform a particular action (especially one as dangerous as chasing, capturing and killing another animal) if it disliked doing so.   Consequently, in order to ensure that an action so crucial to their survival continues, predators have probably evolved to gain some enjoyment from hunting.   Think about reproduction - in order to ensure they're passed to successive generation, our genes programme us to be rewarded (with the 'hormone of love', oxytocin) for having sex.   If sex wasn't fun, nobody would engage in it and the species would die out (test tubes and geneticists notwithstanding!).

So, do foxes enjoy killing?   Yes, they probably do.   However, does enjoying the hunt make them "wicked"?   Quite simply, no. So far as anyone has been able to tell, predators are indifferent, even apathetic, to the lives or “feelings” of their prey, in the same way that their prey is indifferent to the lives and feelings of their predators!   Predators just do what they do.   The adjectives “malicious” and “evil” are often used when referring to the predatory behaviour of foxes (and indeed many predators).   I think that Aidan Martin sums up this debate quite nicely on his ReefQuest site.    Aidan writes:

“Sharks lack a moral code, which is a necessary prerequisite for choosing to behave in a manner that could be called ‘evil’.   Sharks simply do what they do without ill will or premeditation and thus cannot be labelled ‘malicious’.”

Although the above statement refers to sharks, it does well for foxes (or any other predator).   In fact, the only animal to which it does not apply is a human!   Humans have a moral code -- that is, a set of often-complex statements of right and wrong -- and, under most circumstances, an ethical code - predators do not.   With this in mind, it seems rather unhelpful to judge predators by our own cultural values.

The act of hunting can generally be broken down into a series of discrete events: Searching; Detection; Approach; Stalking; Chasing; Capture; and Kill.   I use the term “generally” because any given hunt may not involve all of these, and the sequence of events referred to as “hunting” varies greatly depending on the circumstances.   Indeed, according to Hans Kruuk, Professor of Zoology at Aberdeen University, hunting depends on both prey and environment, coupled with the predator’s own motivation and hunger.   If prey is easily available (i.e. none of the risks associated with the chase and capture are present), then a predator doesn’t need to be hungry to readily take the quarry.   This scenario -- where a predator kills without the motivation of hunger, or kills more than is necessary to sate its hunger -- is referred to as Surplus Killing.  

Surplus killing is not a feature unique to foxes; wolves, leopards, caracals, coyotes, hyenas, bears, shrews, mink, polecats and weasels are among some of the many species known to surplus kill.   Indeed, even animals in our homes are guilty of this; domestic cats are a prime example.   One summer, several years back, while clearing some overgrown vegetation at the back of the garden, I made the discovery of what can only be described as a ‘bird larder’.   In the back corner of my neighbour’s garden was a cluster of four or five dead birds.   Now, while I cannot say for certain that my cats were to blame (there are many cats in the neighbourhood), we had received several dead birds on our patio earlier in the summer.   To my mind, this larder was a result of surplus killing by a local cat (communal hoarding is known, but is rare in mammals) – more birds were killed than were needed to satisfy hunger and the surfeit were stored away in a secluded, over-grown corner for later use.

Many hypotheses have been proposed to explain the occurrence of surplus killing and they can generally be divided into two schools of thought: exploitation of a bounty; pathological killing through hyper-stimulation.   The first school consider that surplus killing arises as a result of a predator stumbling across a bountiful food source, which -- because wild animals can never be sure where the next meal is coming from -- they exploit it to its full potential.

The second school believe that surplus killing is a form of so-called “pathological killing”.   In other words, predators do not know how to react when prey fail to run away – a situation that is not “normal” in nature, so the predator has not evolved to deal with it.   In a fascinating 1972 review of surplus killing in carnivores, Hans Kruuk set out the idea of pathological killing.   Prof. Kruuk proposed that this ‘killing orgy’ may result from a predator’s killing mechanism being continually sparked off by the stimulus of one prey animal after another to catch – in effect, the predator’s instinct to kill prey is being over-stimulated.   Under most circumstances, prey animals in the vicinity of a victim have fled by the time the kill has been made; thus, there are no more prey to chase.   With all this in mind, surplus killing events do seem to have one common feature: there is a lack of defence by the prey.   The prey may be in an enclosure, they may have lost their anti-predator mechanisms through domestication, or they may be restricted by adverse weather conditions (e.g. storms, moonless nights, snow etc.).   In his book Hunter and Hunted, Prof. Kruuk suggests that, because hunger only motivates a predator in the early stages of a hunt sequence, even a sated predator will continue to take prey if the necessity for search, stalk, chase etc. have been removed (although a sated predator will not search for more food).   Moreover, Prof. Kruuk notes that predators have no specific inhibition (with the exception, perhaps, of fatigue) to stop killing if prey is in abundance.  (Photo: Remains of a bird killed by a fox)

The effects of surplus killing events on prey populations are largely unknown, although instances of surplus killing are rare, suggesting that prey populations probably have sufficient time for recovery.   Indeed, I’m aware of only a handful of instances where surplus killing has driven a prey population close to extirpation.   In one of these cases, during the late 1960s, Red fox numbers had to be artificially-controlled  to prevent the complete removal of a colony of Black-headed gulls (Larus ridibundus - left), which were being killed at a rate of some 200 birds per night, in northern Scotland.   This particular example occurred during a spate of very dark and stormy nights, during which researchers found that they could walk up and pick the birds off their nests; the birds wouldn’t fly up and made little or no attempt to prevent being held by the biologists.   Under normal weather conditions, the birds would take to the air as soon as an observer approached too close and would certainly protest to being picked up.

The act of killing more than you can eat at any given time appears to represent a significant waste, both in terms of the food resource and the predator's energy budget.   According to my dictionary, the verb “waste” suggests, “to use, consume or expend [a resource] thoughtlessly, carelessly, or to no avail” or that a resource is “produced in excess of what is required”.   However, waste can also mean, “fail to take advantage of” a resource or situation.   Immediately we are struck by the idea that, just as a predator may be considered to have ‘wasted’ a resource by killing more than it requires to sate its hunger, the animal could similarly be considered to have ‘wasted’ the opportunity to obtain more food when the situation arose by not killing to surfeit!   I consider this to be something akin to going to the supermarket and buying your weekly shopping.   You pick up a joint of meat and put it in the trolley, despite the fact that you’re probably not planning to consume that meat for a few days -- perhaps Sunday lunch -- and, for that matter, you’re probably not even hungry while traipsing up and down the aisles.   You’ll probably now stick the joint in the freezer until Sunday morning, when it will come out to be defrosted.    I consider it unlikely that you expend more energy doing one weekly shop than you would were you to venture into the supermarket to buy only what you needed for the day ahead.

Similarly, surplus killing can only really be considered a waste of energy for a predator if they expend more energy killing prey individuals in a single ‘hit’ than they would killing the same number individuals over a prolonged period of time.   Ergo, if a fox expends X calories killing 20 chickens in a coop, this act only represents a waste of energy if the same fox were to expend less than X cal killing one chicken per night over, say, 20 nights.   The exception to this idea is if the fox is in someway prevented from eating its kills.   If the fox is discovered before it can move all the chickens, or it’s cache of chickens is raided by another animal, then the energy expended by the fox to kill the chickens provides no benefit to the fox’s direct fitness and the surplus killing event could then be considered a waste of the fox’s energy.

Some might argue that there is the added energy “expense” of caching all this prey, which isn’t present if the predator killed only what it needed.   This is certainly true.   However, although the expense of caching 20 birds is reduced -- I shy away from ‘removed’ because leftovers from a single bird may well still be cached -- there is the added outlay of returning to the coop, gaining entry, chasing and killing another chicken.

The idea that surplus killing represents a waste of resources seems less likely when we consider that predators often bury (or cache) un-eaten food.   Wildcats (Felis catus sp.), for example, have been observed to put the remains of their meals under logs; stoats (Mustela erminea) and mink (Mustela) larder cache, while pumas (Felis concolor) may scrape branches or leaves over a carcass, presumably in a bid to conceal it.   Polecats (Mustela putorius) are also known to store frogs in their dens after biting the heads to immobilize them.   Still, caching is not infallible -- have you ever cleaned out the kitchen cupboards or fridge and found food that has exceeded its “Best Before” date? -- and some cached food will invariably never be recovered.

Nonetheless, “waste” is a human economic term; in nature, nothing goes to waste.   Another scavenging animal may discover food that has been cached and forgotten about and, even if the cache is not unearthed, there is a barrage of microorganisms (i.e. bacteria, fungi, Actinomycetes and protozoa) and creepy crawlies (e.g. worms, millipedes, sowbugs, ants and various beetles) that will decompose uneaten food.   In time, even the skeleton will -- the very rare event of fossilization notwithstanding -- be reduced to unrecognizable components.   The time taken for a corpse to decompose varies considerably with environment.   According to Kenneth Iserson, in his book Death to Dust: What Happens to Dead Bodies, if you bury an adult human body about two metres (6ft) into the earth without any embalmment or coffin and in a temperate climate, only the skeleton will remain in about 12 years.   If the body is put in water, decomposition takes about three years, while a body exposed to the air will decompose within about a year-and-a-half.   This is interesting because it highlights how the place of caching is important when considering how long the food will remain in an edible condition.   Hyenas (Crocuta), for example, are known to cache surplus food in shallow water and apparently have considerable success relocating, while leopards (Panthera pardus) tend to cache uneaten food in trees – these examples suggest that hyena and leopard kills would typically decompose faster than those of canids, which tend to bury surplus food.

So, three possible explanations have been put forth to account for the phenomenon of surplus killing – which is correct?   Well, unfortunately, no single theory can suitably account for all cases.   Indeed, there probably isn’t one universal reason to account for all instances of surplus killing.   However, the observation that such events usually manifest where prey with an inability to escape -- through behavioural or physical inhibition -- is in abundance, suggests that surplus killing may, indeed, be the result of a hyper-stimulation of the predator’s killing mechanism.   Whatever the reason, we have seen that there are both advantages and disadvantages to surplus killing.   Among the disadvantages is the possibility that killing to excess will deplete a limited food source that may become essential in times of food stress.   There is also the argument that surplus killing represents a waste of a predator’s energy (although caching seems to at least partially reduce this) and could lead to injuries or even death during the chase or kill.   Conversely, the advantages include the possibility that a predator could consume the carcasses at a later date when hungry again, or that members of the same social group (including offspring) may benefit from the surfeit food.   Alternatively, a predator may use the abundance of easy to catch prey to hone hunting skill that may prove useful in the future.

In conclusion, where anti-predator defence mechanisms have been lost (either through domestication, enclosure, or adverse weather conditions), prey animals are susceptible to significantly higher than normal mortality at the hands of a predator.   It seems the presence of abundant prey that fail to flee causes an over-stimulation of the predator’s killing mechanism.   In this regard, the act of surplus killing seems to be a very unfortunate natural response to an artificial or stochastic situation.   The evolution of caching behaviour by predators goes some way to reducing the ‘waste’ otherwise generated by killing to surfeit, although caching is not infallible and caching invariably cannot utilise all surplus food.   However, even if a cache isn't found by its owner -- or by another animal -- there are an army of microorganisms that will clean-up after a caching fox.   (Photo: It is not always accurate to say that a fox can only carry one prey item at a time - here, a fox runs down an Alaskan highway holding a Ground squirrel, Spermophilus paryii, and a Snowshoe hare, Lepus americanus)     (Back to Menu)

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Q: You say on your fox page that Red foxes tend to scatter cache un-eaten food.   The word “tend” implies that this isn’t always the case.   Are there exceptions to the scatter cache rule and, if so, what are the benefits of scatter caching?

A: I should point out that the ideal of scatter caching is not so much a “rule” as conventional wisdom.   If you look hard enough, there are exceptions to pretty much any “rule” in nature – it’s what makes biological systems so frustrating and, at the same time, so alluring!   Indeed, not all fox species are known even to cache food – for example there is no evidence of food caching in the Blandford’s fox (Vulpus cana).   Anyhow, although scatter caching seems more common than larder caching (or larder hoarding) both behaviours have been observed in Red foxes (Vulpes vulpes).

First, a little background.   Caching seems to be a flexible behavioural response to a surfeit of food by a predator relying on prey whose abundance fluctuates considerably.   J David Henry observed foxes as young as six weeks old caching food, suggesting some genetic predisposition to hiding leftovers.   Conventionally, it was believed that larder hoarding was more efficient for territorial species -- because the larder would be clumped and located within the area of greatest activity -- while non-territorial animals would scatter cache (because scatter caches tend not to be defended).   However, foxes -- which will defend their territory -- seem to employ scatter caching as the ‘norm’, with larder caching being the exception.   (Photo: Very young foxes are well known to cache food, suggestions some genetic predisposition to do so)

Foxes are -- as a function of a small stomach and reduction in skeletal mass -- much lighter than canids of similar physical dimensions.   The Irish terrier and English foxhound, for example, have similar physical dimensions to Red foxes, but are nearly twice the mass.   Studies on the stomach capacities of foxes have shown that these animals have proportionally smaller stomach sizes compared to many other canids.   For example, a Red fox can consume a maximum of about 10% of its bodyweight in a single sitting, while a Grey wolf (Canis lupis) may consume as much as 20%.   As a result, the largest individual foxes are only capable of consuming a kilo of meat per sitting, with many of the smaller (more average-sized) individuals eating only half a kilo.   Consequently, should a fox stumble across easily obtainable prey, the remains of a wolf kill, or some other bountiful source, excess food is carried away and buried for later use.

The type of cache foxes use, as well as the extent to which they attempt to conceal the cache, varies between individuals, improves with age and is related to both the availability of food and the ‘value’ of the food.   In their book Urban Foxes, Steve Harris and Phil Baker note that the urban foxes of Bristol would often cache their quarry rather haphazardly, leaving feathers and wings sticking out from the ground.   Conversely, in his 1986 book, David Henry reports that, of the hundreds of fox cachings he witnessed in the boreal forests of Canada, each site was carefully chosen and the caching process meticulously implemented – one fox was observed to walk backwards away from his cache hole, carefully erasing his footprints from the snow as he went!   Indeed, it appears that the care with which food remains are cached is largely dependant upon the ‘value’ of, and the fox’s preference for, the food item.   Foxes tend to cache high-value foods (such as meat) more carefully than they do lower value items (such as fruit, vegetables and cleaned bones).   In a 1976 paper to the German journal Zeitschrift fur Psychologie, David MacDonald reported foxes caching preferred prey -- such as Field voles (Microtus agrestis) -- more consistently than less-preferred prey, like Bank voles (Myodes glareolus).

Most detailed observations on fox caching behaviour have revealed a tendency to scatter cache their leftovers.   Economically, this seems to make good sense: don’t put all your eggs in one basket (or all your food in one hole)!   During his many hours of fox observation in Canada, David Henry undertook a series of impressively ingenious experiments to assess the benefits of scatter caching.   Dr Henry wandered around the forests, burying small amounts of tinned dog food; first in a scattered pattern and then in a larder caching fashion.   He made detailed maps and notes of where each hoard was buried and returned to each a short time later to see if any marauding animals had discovered the cache.   Dr Henry found that when he larder cached his meat, an average of six caches (out of his total of 15) remained, while seven of the scatter cached hoards (again out of 15) were still buried.   These results didn’t suggest much until he calculated the Standard Deviation (a statistical indication of how much a set of numbers vary from the mean).   It transpired that the standard deviation of the larder hoards was much higher than it was for the scatter caches (6 + 4.39 compared with 7 + 1.67).   In other words, scatter caching doesn’t reduce the mean number of caches that are likely to be discovered by ‘robbers’; instead scattering makes these inevitable losses more regular, more uniform and ultimately more predictable.   Ergo, it would seem from Dr Henry’s results that scatter caching increases the chances that at least a portion of the caches will still be there when the fox needs it.   (Photo: A fox leaves to cache a piece of meat)

So, taking Dr Henry’s results into consideration, we have some idea why foxes may be more prone to scatter caching leftover food than hoarding it in a larder hole.   However, larder caching does still occur.   J Sande observed a Red fox in Sweden repeatedly putting prey into the same hole.   Examination of the cache found it to contain a hare, ten field mice and a grouse.   Similar observations of both Red and Arctic foxes on Baccalieu Island off Newfoundland by Bohdan Sklepkovych, currently at the University of Stockholm in Sweden, have shown larder-caching tendencies in both species.   In a 1994 paper, Dr Sklepkovych reports that seabirds -- especially Leach’s Storm petrels (Oceanodroma leucorhoa) -- captured and hoarded prior to the onset of winter composed the largest proportion of the Red fox’s winter diet.  Indeed, a later study reported that Storm petrels made-up a minimum of 53% to 63% of fresh scat collected in February, despite the birds’ absence from the island between November and April.

A 1996 paper to the journal Arctic, Dr Sklepkovych and his colleague, William Montevecchi at the Memorial State University in Canada, looked at food hoarding behaviour of Red and Arctic foxes on Baccalieu Island.   The biologists concluded that larder hoarding was associated with a superabundance of food and that it appears to represent a flexible response to changing environmental conditions.   In one example cited by Drs Sklepkovych and Montevecchi, a larder discovered in 1985 had 16 holes and 385 out of the 396 (97%) carcasses inside were Leach’s Storm petrels!   They observed both larder and scatter caches from their foxes, witnessing two distinct ‘types’ of larder hoard: (1) one or more holes naturally occurring or actively dug beneath boulders; and (2) several holes dug vertically into the soil to a depth of about 1m (3ft).   Interestingly, no attempt was made to conceal the hoard at ground level, suggesting a superabundance of prey.   Sklepkovych and Montevecchi also found that decomposition in the caches was often reduced -- the microclimate was noticeably cooler than the ambient -- and three freshly-killed petrels placed under a rock in July 1986 showed little sign of dehydration and were all well preserved when checked some four months later.   (Photo: Not only do foxes possess a keen ability to recovered buried food, they're also good at finding other predator's left-overs)

So, we know that both larder and scatter caching are known in Red foxes and we know that scatter caching serves to make losses more uniform.   However, what is the likelihood of a fox ever returning to its cache?   Well, much of the data available suggest that foxes have a good spatial memory, aided by the use of urine and faeces to mark cache sites.   In their 1996 paper Drs Sklepkovych and Montevecchi found that of 67 petrels caught by two foxes, 22 (33%) were eaten, while all but two of the remaining birds were partially eaten before being cached in one of 45 scatter hoards.   Of those cached, 12 (28%) were recovered within 24 hours, 17 (41%) within two days, 22 (53%) within one week, 26 (62%) within two weeks and 1 within three weeks.   This suggests that at least 62% of the caches were recovered during the study period and, whether or not foxes subsequently recovered the remaining caches is unknown.   Oxford University’s David Macdonald and three colleagues reported higher recovery rates in a 1994 paper to the Journal of Mammalogy.   During their study in Dalyan, on the coast of Southwest Turkey, Prof Macdonald and his co-workers found that Red foxes retrieved 94% of scatter cached Loggerhead turtle (Caretta caretta) eggs (no larder hoarding was observed), 80% on the subsequent night.

Fox cache sites may be marked with either urine or faeces, apparently depending on their contents.   In his book Red Fox: The Catlike Canid -- and in a 1977 paper to the journal Behaviour -- Dr Henry notes that where foxes cache more durable items (like bones), they mark the cache with more durable scent (i.e. faeces).   Generally, however, foxes will only mark caches after they’ve been emptied and, as such, he considered this urination to be a sort of ‘bookkeeping’ method.   Dr Henry observed that the foxes would urinate on the cache after the food had been recovered and consumed (or moved elsewhere), possibly to prevent the fox wasting time and energy looking for food that is no longer there.   However, there did seem to be some ambivalence in this behaviour, because if the smell of food was still sufficiently strong, the fox would ignore the smell of urine and excavate the ground anyway.

In conclusion, although foxes scatter cache with greatest frequency, larder caching has been observed.   Scatter caching appears to serve as a method for regulating losses of hoarded food to robbers, making any losses more regular and uniform.   Where larder hoarding is observed, it appears to be a flexible behavioural response to a superabundance of available prey.  (Back to Menu)

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Q: Are Foxes Colour-blind?

A: The short answer to this is: probably not!   First a little background.   At school you were probably taught about something called the Electromagnetic Spectrum (or EMS), which represents the complete range of electromagnetic radiation, from the longest radio waves to the shortest cosmic waves.   We call this range the “Electromagnetic Spectrum” because it is composed of electromagnetic radiation.   We need not concern ourselves with what electromagnetic radiation actually is -- although it is basically radiation consisting of an electric and magnetic field that are at right-angles to each other and the direction in which they’re travelling -- but we should be aware that we can only see a small percentage of it.   The wavelengths of light that we can see fall into the category of “Visible Light”.

We classify electromagnetic radiation based on its wavelength (see figure below).   Wavelengths of radiation are measured in units called “nanometres” (abbreviated to "nm"); one nanometre is one thousand-millionth of a metre or, to put it another way, there are 10 million nanometres in a centimetre (or nearly 25 ½ million in an inch).   Visible light is radiation with a wavelength of between 380nm and 780nm – wavelengths between these values represent different colours of light.   For example, light with a wavelength of 740 to 620nm is red, while that between 575 and 500nm is green.

We are able to see the world around us because our eyes pick up visible light reflected by objects in our surroundings; the colours we see are dependant on the wavelength of the reflected light.   The stationary organizer on my desk, for example, appears red because it absorbs all colours of visible light except red, which it reflects.   Light bounces back from objects and enters our eye through the pupil, striking the light-sensitive membrane at the back of our eye called the retina.   In fact, during development of the embryo, part of the neural tube -- which goes on to develop into the central nervous system -- forms an outcropping, which extends and develops into the retina – the retina is consequently considered part of the brain.

Cells on the retina can be divided into two broad types: rods and cones.   Rods are sensitive to very low levels of light, but are monochromatic (i.e. don’t detect colour), which is why in conditions of very low light (i.e. dusk and at night), we see objects in greyscale.   Consequently, rod cell vision is often referred to as “scoptic” or “twilight” vision.   The rod cells are also used for detecting movement.   Conversely, cone cells are sensitive to bright light and colour.   In the human eye, we recognise three different ‘types’ of cone cell, separated by their colour pigment: red (peak at 570nm); green (535nm); and blue (445nm).   The colours we see are determined by which combination of sensors are excited and, because most humans have these three pigments, the human eye can sense almost any gradient of colour when red, green and blue are mixed.

The presence of three colour-sensitive pigments is referred to as trichromatic vision.   Humans are not the only mammals with three cone types, cats as well as certain apes, chimps and African monkeys also have three colour-sensitive pigments.   However, the presence of these pigments doesn’t necessarily mean that they see colour in the same way as humans.   Although cats have three cone pigments, they have slightly different peak sensitivities, leading to a more pastel-coloured vision, with less saturation than humans can register.

There are some inherent pitfalls in trying to assess the presence of colour vision based solely on the number of colour-sensitive (cone) cells on the retina.   Moreover, there is the problem that colour is highly subjective - I might call something red, while you might think that it was pink and someone else might plump for orange!   Generally, psychometric tests are also needed to assess the colours that animals are able to see and respond to.   However, although the psychological experiments have yet to be applied to foxes, studies on their retinal topography -- that is to say, studies looking at the type and distribution of cells on the retina -- have shown that foxes certainly have the ‘equipment’ to register some colour, although the degree to which foxes (and dogs in general) are able to resolve colours is probably less than ours.   Indeed, given the roles that dogs play in our daily lives (perhaps most importantly as guide dogs), it is something of an oddity that there are so few studies looking at the vision of canids – many of those that do exist have produced dubious or conflicting results.

Observations on the activity patterns of canids do suggest that they are “visual generalists”, able to work in conditions of various light intensities.   For example, I’ve just returned from walking our dog – the weather is bright and sunny and she chased anything that moved as we meandered around the forest.   Similarly, anyone who has taken their dog out at dusk or at night can vouch for the fact that, while they may not be able to see the path they’re walking on, their dog is off investigating the undergrowth.   Observations of fox movements suggest that they are able to cope with a wide variety of light conditions; foxes are active during dawn, daytime, dusk and throughout the night.

Although foxes and other wild canids are known to be arrhythmic (i.e. active during the day and night), much of their hunting and foraging occurs from dusk to dawn and, as might be expected, studies on canid retinas have revealed a predominance of rod cells (about 97% in dogs and wolves), suggesting that their sight in dim light and ability to differentiate shades of grey and movement is superior to ours.   In a 1993 study published in the journal Visual Neuroscience, a team at the University of California looked at the photopigments (i.e. light-sensitive chemicals) of dogs and foxes.   The optometrists found that all the canids in their study possessed two cone pigments, one with a peak sensitivity of about 555nm (light green) and another with a peak between about 430 and 440nm (dark blue / purple).   In the Red fox (Vulpes vulpes), this second (short-wavelength) peak was at 438nm.   These findings imply that foxes have dichromatic (i.e. two-colour) vision similar to that of a human deuteranope – in other words, it suggests that foxes are red-green colour blind.

Studies on the distribution of rod and cone cells on the retina’s of canids has shown that, although some species do apparently show an increase in cone density towards the centre of the retina, dogs do not have a fovea (the region on a human retina composed entirely of cones that you’re using to read this article).   The lack of a fovea suggests that a dog’s ability to discriminate details is less than ours.   Indeed, some authors have estimated that a dog’s eye for detail is about six times worse than ours.   Similarly, a recent study by a team of biologists at the University of Vienna reported that brightness discrimination ability in dogs is about two-times worse than in humans.

Thus, in conclusion we can say that foxes -- and dogs in general -- are not colour blind; they possess dichromatic vision that effectively makes them red-green colour blind.   The lack of a fovea in canines also implies that humans are able to discern details twice as well as dogs.   However, dogs do have a significantly better ability to discriminate between shades of grey than humans, coupled with a capacity to detect movement and see objects in conditions of dim light (thanks to a reflective tapetum) that’s superior to ours.

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Q: I have taken in an injured fox cub and would like to keep it as a pet – is this illegal?

A: In short, no, in Britain it is not illegal to keep a Red fox (Vulpes vulpes) as a pet.   It is, however, ill-advised.

During the late 1960s and early 1970s, the UK experienced a trend of people keeping exotic animals (including various hybrids) as pets; this fuelled a growing concern for public safety.   On the 22^nd July 1976, UK Parliament voted in “An Act to regulate the keeping of certain kinds of dangerous wild animals”.   The legislation was called the Dangerous Wild Animals Act and, under section 5, it prohibits the keeping of “any dangerous wild animal except under the authority of a licence granted in accordance with the provisions of this Act by a local authority.”   Chapter 38 of the Act sets out a list of the animals for which a licence must be obtained; it covers various species of bird and mammal, along with the crocodilian reptiles, snakes and several genera of lizards, spiders and scorpions.   Among the mammals, the list covers all of the Canidae (dog family), with the exception of the foxes (genera: Alopex, Dusicyon, Otocyon, and Vulpes), Raccoon dog (Nyctereutes procyonoides) and, of course, the domestic dog (Canis familiaris).   To this extent, one could freely keep a fox as a pet without the need to obtain a licence from your local council.

However, the fact that a licence isn’t required to keep a Red fox does not mean that you are without any legal obligation.   Foxes brought into captivity fall within the constraints of the Protection of Animals Act of 1911 (with various amendments).   Under this legislation, it is a criminal offence to cause “unnecessary suffering” to any animal in your care – this can include a failure to provide suitable food, water, shelter or veterinary care.   Successful conviction under this Act can result in a £5,000 fine, up to six months in prison, or both.   Additionally, any animal under the care of a human falls within the remit of the Animal Welfare Act of 2006 – the act created in November 2006, but didn’t become law in the UK until April (March in Wales) of 2007.   Sections one and two consider a person to have committed an offence if "an act of his, or failure of his to act, causes an animal to suffer"; this means that even watching someone else cause an animal 'unnecessary suffering' and failing to do something about it is treated as an offence under this Act.   Section nine of the Act set out the duty of care a person has towards an animal in their care, stating that:

"A person commits an offence if he does not take such steps as are reasonable in all the circumstances to ensure the needs of an animal for which he is responsible are met to the extent required by good practice."

The Act considers "an animal's needs" to include:

-          its need for a suitable environment

-          its need for a suitable diet

-          its need to be able to exhibit normal behaviour patterns

-          any need it has to be housed with, or apart from, other animals

-          its need to be protected from pain, suffering, injury and disease.

This legislation also covers the mutilation of animals, causing animals to fight and even tail-docking of dogs.   In addition to fines (up to £20,000) and prison sentences (up to one year), Section 35 of the Act states that any person convicted under the legislation can be disqualified from owning, keeping, or participating in the keeping of animals.   The Protection of Animals Act and Animal Welfare Act work in conjunction with a third law, the Abandonment of Animals Act, which we shall look at in a moment.

Despite being legal, keeping previously-wild foxes -- those bred and sold by the pet trade are a different case -- as pets should be strongly discouraged.   Raising a rescued wild fox is not the same as caring for a domestic dog.   Foxes can be very boisterous and destructive as they grow.   They will require some form of containment (i.e. a cage or pen) in order to prevent/minimise potential damage to the house or garden and have a considerable amount of energy (they’re almost insatiably curious), which must be taken into consideration.   The extremely potent anal gland secretion and urine, which are employed as scent marking along the boundaries of the animal’s territory, mean that foxes can also smell strongly.   It is possible to have the anal glands surgically removed and/or have the animal spayed or neutered (the latter an attempt to modify the fox’s behaviour), although such operations rarely achieve the desired result.   Foxes can be very difficult to house-train and, while they can be trained -- as one would a dog -- to a limited extent, levels of obedience can be considerably lower than for domestic dogs, which have been selectively bred for their servile demeanour.

The provision of veterinary care is a consideration that must be addressed to ensure the fox remains healthy.   Most veterinarians in the UK are probably capable of dealing with a fox – many already deal with wildlife casualties and, I suspect, most would treat a fox as though it were a domestic dog.   The fox would need to be vaccinated against the various diseases contracted by domestic dogs, including canine distemper, Leptospirosis, infectious canine hepatitis, rabies and canine parvovirus (or ‘parvo’).   The latter of these is a highly infectious disease caused by viruses of the Parvoviridae family that typically manifests in two forms: intestinal parvo (which attacks the immune system, destroying rapidly dividing cells such as those in the lymph nodes and bone marrow) and the less common cardiac parvo (which, as the name suggests, attacks the heart).   Dogs can contract the virus through contact with infected surfaces and material, including infected faeces and soil.   Thus it is important to ensure a pet fox, just like a pet dog, is vaccinated against parvo.   Between 1991 and 1995, a team of biologists led by Uwe Truyen at the University of Munich’s Institute for Medical Microbiology collected blood sera from Red foxes in Germany to test for canine parvovirus, canine distemper virus, canine adenovirus and canine herpesvirus.   The biologists found that 65 (13%) of the 500 samples they collected tested positive for parvo and, in their 1998 paper to the journal Epidemiology and Infection write that:

“… the sudden emergence of canine parvovirus in the domestic dog population may have involved the interspecies transmission between wild and domestic carnivores.”

Thus, foxes can contract parvo from domestic dogs and dogs can invariably catch parvo from foxes – especially when we consider that many dogs display a penchant for rolling in fox scat.

I have heard stories from people in Britain who have kept foxes as pets, which suggest these animals can make excellent companions.   In some cases they probably do.   However, there are also many cases where they invariably fail to live up to their owner’s expectations and are either given up to a wildlife centre, dispatched or abandoned.   In the UK (excluding Northern Ireland), the Abandonment of Animals Act (June 1960) makes it a criminal offence to leave an animal "in circumstances likely to cause the animal any unnecessary suffering".   While one might be inclined to argue over the term “unnecessary”, abandoning an animal that is unable to ‘look after itself’ is treated as an act of “cruelty” as set out by Section 1 of the 1911 Protection of Animals Act.   Unfortunately, cases of pet foxes being abandoned are not uncommon.   To the best of my knowledge there are no official figures on the number of foxes kept as pets in the UK, or the number abandoned each year, but Vale Wildlife Hospital & Rehabilitation Centre founder and manager, Caroline Vale, told me:

“… every year we have to take in at least one cub that has been hand-reared & then discarded when it gets older & starts to smell or becomes aggressive.”

Indeed, on their website, Vale Wildlife Rescue has short profiles of several foxes that have been taken in after apparently being kept as pets before being dumped.   Seven-year-old dog fox “Bart”, for example (photo, left), was taken in by the centre after being found wandering in Birmingham’s Sutton Park wearing a collar.

A big problem for Vale, and many other rescue centres, is that foxes taken in as cubs and raised to adulthood as pets often become imprinted.   Imprinting, as Arizona State University’s John Alcock describes it in his 2005 book Animal Behavior, is the process by which: “a young animal’s early social interactions, usually with its parents, lead to its learning such things as what constitutes an appropriate sexual partner”.   Imprinting, which is now often lumped together with what behaviourists refer to as “associative learning” (despite the latter generally involving a reward), was first described by ethologist Konrad Lorenz.   In his 1952 book, King Solomon’s Ring, Dr Lorenz described how he was able to imprint himself on greylag goslings (Anser anser) such that they followed him everywhere thinking that he was their parent.

Numerous studies, especially on birds, have shown that when animals fostered by a different species reach sexual maturity, they typically try to mate with members of the fostering species.   Between 1998 and 2000, for example, a team of biologists at the University of Oslo in Norway led by Tore Slagsvold studied the effect of cross-fostering on Blue tits (Cyanistes caeruleus) and Great tits (Parus major).   The researchers put blue-tit eggs into great tit nests and vice versa – actually, they put the eggs into Coal tit (Parus ater) and Pied flycatcher (Ficedula hypoleuca) nests too, but it’s the Great tits we’re really interested in.   The male great tits raised by blue tits tried to pair with female blue tits, while blue tits found mates with other blue tits, regardless of the species that fostered them.   These data provide a superb example of how imprinting can have different consequences for different species.   Recent neurological studies of imprinting have suggested that it may be a two-stage process: there is a ‘critical period’ during which the initial imprinting occurs, followed by a period of stabilisation (involving courtship attempts) during which morphological changes are made to some of the neurones.   Regardless of the science behind it, the problem of imprinting can be a significant one, as Caroline Gould went on to explain:

“Whether or not an imprinted cub can be released depends on exactly how imprinted it is. If it is passed on to us when it is under 6 months or so old, then it will almost certainly revert once mixed with other wild cubs, but when we get them at, for example, 12-18 months old, which is not uncommon, it is virtually impossible to get them back into the wild & then they do have to spend the rest of their lives in captivity (or the alternative is euthanasia).”

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