A familiar sight in the British countryside, the rabbit was first introduced by the Romans around 43AD for meat and fur, although the species doesn't appear to have become established until the Normans introduced more in the mid-12th Century. In the 1940s numbers were so high and the damage to crops so significant that the myxomatosis virus was introduced, resulting in the population crashing by some 99% in only a couple of years. Numbers recovered and there were estimated to be about 50 million in Britain during the mid-1990s. More recently, numbers appear to have declined again and survey data from the British Trust for Ornithology suggest the population may have declined by as much as 60% since 1995, largely in response to Viral Haemorrhagic Disease.
That which follows is a summary of European rabbit natural history.
The European rabbit at a glance
The separation of burrow-living rabbits from the non-burrowing hares was only accepted, taxonomically, in the early 1900s and, prior to this, rabbits were classified as Lepus cuniculus. The European rabbit’s Latin name, Oryctolagus cuniculus, translates roughly as ‘hare-like tunnel digger’ and alludes to a way of life that involves digging sometimes complex burrow systems.
Size & Appearance: Significantly smaller than hares, with proportionally much shorter ears and shorter hind legs. Grow to 34-50cm (1-1.6 ft.) in length, with another 4-8cm of tail, and weigh ca. 1.2-1.5kg (2.6-5.5 lbs). Size of the ears particularly helpful when separating from hares. Rabbit ears shorter than head length. Fur colour is variable but typically grey-brown on the back and blue-grey on stomach, with a red/ginger patch on the back of the neck. Ear tips are brown (hares are black) and tail has a black upper surface and is white below.
Distribution: Native to semi-arid regions of Iberian Peninsula (i.e. Spain and Portugal) in southwestern Europe, and Morocco and Algeria on north African continent. Now found widely throughout Europe, from Ireland in the west to Poland and Ukraine in the east and north into southern Sweden courtesy of human introductions. Also introduced populations in Australia, New Zealand, Chile and the Falkland Islands in the south Atlantic.
Longevity/Mortality: Typically live for 3-4 years, although about three-quarters die in the first three months; early born kittens have higher survival probability than later litters. Overall, first year morality of 95% not unexpected. Many pet rabbits live 9-10 years; oldest wild rabbit on record, tagged in Poland, lived to 12 yrs. Rabbits are prey for ~45 different species of predator including foxes, badgers, weasels, stoats, domestic dogs and cats, wildcats and various birds of prey and gulls. Long-running debate over what part predators play in reducing rabbit numbers. Populations appear largely driven by climate (i.e. habitat quality/food availability), accidents (esp. burrow collapse and drowning), agricultural development and disease.
Sexing: Difficult to sex without handling or behavioural cue. Females typically have a narrower head, with the profile from ears to nose somewhat less rounded compared to males. Females are “does”; males “bucks”.
Activity: Nocturnal in many populations, with clear daily cycle of activity: emerge from warren at dusk, feed throughout the night, and return to warren in early morning. Quick to adapt to human activity and, in areas of reduced persecution, can become progressively cathemeral. Even in largely undisturbed populations, diurnal activity typically resting or preening with some feeding; most feeding and socialising occurs at night. Strong winds, heavy rain and full moons reduce activity.
Territory/Range: Highly adaptable. Found in heathland, grasslands, meadows, deciduous woodland, sandy soils (e.g. sand dunes), mixed farmland and cliffs up to ca. 500m (1,600 ft); appear to avoid conifer forests. Home range varies widely according to rabbit density and habitat type, but typically 0.3-0.7 hectares (0.75-2 acres), with males ranging further than females.
Diet: Entirely vegetarian, but have catholic diet that includes crops (e.g. germinating cereals, young trees, lettuce, cabbages, root vegetables, etc.), grasses, buds, bulbs and bark (particularly during winter). Food passes out of small intestine into large intestine, which is split into a bacteria-rich fermenting chamber (caecum) and the colon leading to anus. Food passes into caecum, where it is broken down by chamber peristalsis; periodic powerful contraction flushes part caecum contents into colon through wall-like structure (haustra) that filters out large particles (>100µm) that are coated in mucoprotein rich in vitamins and microorganisms. These ‘capsule type’ soft faeces (caecotrophs) pass into colon and out, being eaten directly from the anus by the rabbit. Lab studies suggest rabbits rapidly lose condition if they cannot access their caecotrophs; fatal if deprived for more than two weeks. Pellets swallowed whole (no chewing) so the membrane remains intact and pellet remains whole in stomach for several hours while the microorganisms breakdown the plant material inside, releasing nutriment. Once the food particles fall below 100µm threshold, they’re passed out as small, hard, dry pellets.
Reproduction: Significant reproductive potential can increase population quickly. Sexually mature early (14-16 wks old); induced ovulators with postpartum oestrous (i.e. don’t have specific breeding seasons as mating stimulates ovulation, and can conceive straight after having given birth). Gestation period of 28-33 days and average litter size of five pups/kittens. Females could potentially produce 50 pups in single year, but few seem to exceed 10. Despite lack of breeding season, most kittens born February-August; April-June is peak period for pregnancies. Pregnant does compete for prime breeding chamber(s) in warren; generally occupied by does with highest social rank. Low ranking does must often dig own single-chambered breeding den, called “stop”. Nest chamber lined with grass, moss and fur pulled from belly, and into this pups are born; naked, blind and weighing 30-35g (ca. 1oz.). Once litter is complete, doe will nurse for <1 minute and leave. Mother visits briefly once each day, generally staying for only a few minutes to suckle (anti-predator strategy). Kits start moving around nest after ~7 days and eyes open ~10 days, shortly after which they will make brief forays out of nest chamber. Doe seems largely disinterested in kittens; doesn’t brood them, seldom cleans them and doesn’t retrieve any that stray. Lab studies suggest kittens forage for same food mother eats, possibly cues transmitted in milk or caecotrophs.
Behaviour & Sociality: Highly territorial using scent to mark out core area boundaries. Each population (colony) subdivided into several distinct groups; normally consist of four or five unrelated males (bucks) guarding up to ~8, generally related, females (does), although social system varies from pairs to up to 20 individuals. Group will maintain core area, typically around breeding warren, that’re defended from neighbouring groups – boundaries marked with scent. Scent deposited from special glands on chin (submandibular glands) and tends to be rubbed on branches and other conspicuous objects within territory. Urine also deposited around territory and hard pellets may be coated in a scented mucus from anal glands before deposition in shallow scrapes (latrines), or on anthills (or other similar locations) along the territory border – such pellets generally darker in colour those not used territorially. Females also mark the entrance to breeding stops with urine and males sometimes spray urine at females during courtship. Largest, most dominant, buck in the group has most well developed scent glands and is responsible for most scent marking done by group. Scent used to allude to group identity, sex, age, social status and reproductive condition. Fighting is common, following ritualised displays with ear position and foot thumping.
Threats: Despite increasing in population in most introduced countries (e.g. UK and Australia), in its native range the rabbit is declining. Estimated decline of 95% since 1950s in Iberian Peninsula and 25% in Portugal since 1995 led to IUCN classification of “Near Threatened”. Decline appears to be largely from viral disease myxomatosis and rabbit haemorrhagic disease. Habitat fragmentation and agricultural intensification likely to be contributory factors.
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