Rabbits, or bunnies, are small mammals in the family Leporidae (which also includes the hares), which is in the order Lagomorpha (which also includes pikas). They are familiar throughout the world as a small herbivore, a prey animal, a domesticated form of livestock, and a pet, having a widespread effect on ecologies and cultures. The most widespread rabbit genera are Oryctolagus and Sylvilagus. The former, Oryctolagus, includes the European rabbit, Oryctolagus cuniculus, which is the ancestor of the hundreds of breeds of domestic rabbit and has been introduced on every continent except Antarctica. The latter, Sylvilagus, includes over 13 wild rabbit species, among them the cottontails and tapetis. Wild rabbits not included in Oryctolagus and Sylvilagus include several species of limited distribution, including the pygmy rabbit, volcano rabbit, and Sumatran striped rabbit.
Rabbits are a paraphyletic grouping, and do not constitute a clade, as hares (belonging to the genus Lepus) are nested within the Leporidae clade and are not described as rabbits. Although once considered rodents, lagomorphs diverged earlier and have a number of traits rodents lack, including two extra incisors. Similarities between rabbits and rodents were once attributed to convergent evolution, but studies in molecular biology have found a common ancestor between lagomorphs and rodents and place them in the clade Glires.
Rabbit physiology is suited to escaping predators and surviving in various habitats, living either alone or in groups in nests or burrows. As prey animals, rabbits are constantly aware of their surroundings, having a wide field of vision and ears with high surface area to detect potential predators. The ears of a rabbit are essential for thermoregulation and contain a high density of blood vessels. The bone structure of a rabbit's hind legs, which is longer than that of the fore legs, allows for quick hopping, which is beneficial for escaping predators and can provide powerful kicks if captured. Rabbits are typically nocturnal and often sleep with their eyes open. They reproduce quickly, having short pregnancies, large litters of four to twelve kits, and no particular mating season; however, the mortality rate of rabbit embryos is high, and there exist several widespread diseases that affect rabbits, such as rabbit hemorrhagic disease and myxomatosis. In some regions, especially Australia, rabbits have caused ecological problems and are regarded as a pest.
Humans have used rabbits as livestock since at least the first century BC in ancient Rome, raising them for their meat, fur and wool. The various breeds of the European rabbit have been developed to suit each of these products; the practice of raising and breeding rabbits as livestock is known as cuniculture. Rabbits are seen in human culture globally, appearing as a symbol of fertility, cunning, and innocence in major religions, historical and contemporary art.
Terminology and etymology The word rabbit derives from the Middle English ("young of the coney"), a borrowing from the Walloon , which was a diminutive of the French or Middle Dutch ("rabbit"), a term of unknown origin. The term coney is a term for an adult rabbit used until the 18th century; rabbit once referred only to the young animals. More recently, the term kit or kitten has been used to refer to a young rabbit. The endearing word bunny is attested by the 1680s as a diminutive of bun, a term used in Scotland to refer to rabbits and squirrels.
Coney is derived from cuniculus, a Latin term referring to rabbits which has been in use from at least the first century BC in Hispania. The word cuniculus may originate from a diminutive form of the word for "dog" in the Celtic languages.
A group of rabbits is known as a colony, nest, or warren, though the latter term more commonly refers to where the rabbits live. A group of baby rabbits produced from a single mating is referred to as a litter and a group of domestic rabbits living together is sometimes called a herd.
A male rabbit is called a buck, as are male goats and deer, derived from the Old English or , meaning "he-goat" or "male deer", respectively. A female is called a doe, derived from the Old English , related to ("to suck").
Taxonomy and evolution
Rabbits and hares were formerly classified in the order Rodentia (rodents) until 1912, when they were moved into the order Lagomorpha (which also includes pikas). Since 1945, there has been support for the clade Glires that includes both rodents and lagomorphs, though the two groups have always been closely associated in taxonomy; fossil, DNA, and retrotransposon studies in the 2000s have solidified support for the clade. Studies in paleontology and molecular biology suggest that rodents and lagomorphs diverged at the start of the Tertiary.
The extant species of family Leporidae, of which there are more than 70, are contained within 11 genera, one of which is Lepus, the hares. There are 32 extant species within Lepus. The cladogram is from Matthee et al., 2004, based on nuclear and mitochondrial gene analysis.
Classification
Order Lagomorpha Family Leporidae (in part): Genus Brachylagus Pygmy rabbit, Brachylagus idahoensis Genus Bunolagus Riverine rabbit, Bunolagus monticularis Genus Caprolagus Hispid hare, Caprolagus hispidus Genus Lepus Genus Nesolagus Sumatran striped rabbit, Nesolagus netscheri Annamite striped rabbit, Nesolagus timminsi Genus Oryctolagus European rabbit, Oryctolagus cuniculus Genus Pentalagus Amami rabbit/Ryūkyū rabbit, Pentalagus furnessi Genus Poelagus Bunyoro rabbit, Poelagus marjorita Genus Pronolagus Natal red rock hare, Pronolagus crassicaudatus Jameson's red rock hare, Pronolagus randensis Smith's red rock hare, Pronolagus rupestris Hewitt's red rock hare, Pronolagus saundersiae Genus Romerolagus Volcano rabbit, Romerolagus diazi Genus Sylvilagus Andean tapeti, Sylvilagus andinus Swamp rabbit, Sylvilagus aquaticus Desert cottontail, Sylvilagus audubonii Brush rabbit, Sylvilagus bachmani Common tapeti, Sylvilagus brasiliensis Mexican cottontail, Sylvilagus cunicularis Dice's cottontail, Sylvilagus dicei Eastern cottontail, Sylvilagus floridanus Central American tapeti, Sylvilagus gabbi Tres Marias cottontail, Sylvilagus graysoni Robust cottontail, Sylvilagus holzneri Omilteme cottontail, Sylvilagus insonus Mountain cottontail, Sylvilagus nuttallii Appalachian cottontail, Sylvilagus obscurus Marsh rabbit, Sylvilagus palustris Santa Marta tapeti, Sylvilagus sanctaemartae Coastal tapeti, Sylvilagus tapetillus New England cottontail, Sylvilagus transitionalis Venezuelan lowland rabbit, Sylvilagus varynaensis
Differences from hares
The term rabbit is typically used for all Leporidae species, excluding the genus Lepus. Members of that genus are known as hares or jackrabbits.
Lepus species are precocial, born relatively mature and mobile with hair and good vision out in the open air, while rabbit species are altricial, born hairless and blind in burrows and buried nests. Hares are also generally larger than rabbits, and have longer pregnancies. Hares and some rabbits live relatively solitary lives above the ground in open grassy areas, interacting mainly during breeding season. Some rabbit species group together to reduce their chance of being preyed upon, and the European rabbit will form large social groups in burrows, which are grouped together to form warrens. Burrowing by hares varies by location, and is more prominent in younger members of the genus; many rabbit species that do not dig their own burrows will use the burrows of other animals.
Rabbits and hares have historically not occupied the same locations, and only became sympatric relatively recently; historic accounts describe antagonistic relationships between rabbits and hares, specifically between the European hare and European or cottontail rabbits, but scientific literature since 1956 has found no evidence of aggression or undue competition between rabbits and hares. When they appear in the same habitat, rabbits and hares can co-exist on similar diets. Hares will notably force other hare species out of an area to control resources, but are not territorial. When faced with predators, hares will escape by outrunning them, whereas rabbits, being smaller and less able to reach the high speeds of longer-legged hares, will try to seek cover.
Descendants of the European rabbit are commonly bred as livestock and kept as pets, whereas no hares have been domesticated, though populations have been introduced to non-native habitats for use as a food source. The breed known as the Belgian hare is actually a domestic rabbit which has been selectively bred to resemble a hare, most likely from Flemish Giant stock originally. Common names of hare and rabbit species may also be confused; "jackrabbits" refer to hares, and the hispid hare is a rabbit.
Domestication
Rabbits, specifically the European rabbit (Oryctolagus cuniculus) species, have long been domesticated. The European rabbit has been widely kept as livestock, starting in ancient Rome from at least the first century BC. Selective breeding, which began in the Middle Ages, has generated a wide variety of rabbit breeds, of which many (since the early 19th century) are also kept as pets. Some strains of European rabbit have been bred specifically as research subjects, such as the New Zealand white.
As livestock, European rabbits are bred for their meat and fur. The earliest breeds were important sources of meat, and so were bred to be larger than wild rabbits at younger ages, but domestic rabbits in modern times range in size from dwarf to giant. Rabbit fur, produced as a byproduct of meat production but occasionally selected for as in the case of the Rex rabbit, can be found in a broad range of coat colors and patterns, some of which are produced via dyeing. Some breeds are raised for their wool, such as the Angora rabbit breeds; their fur is sheared, combed or plucked, and the fibers are spun into yarn.
Biology
Evolution The earliest ancestor of rabbits and hares lived 55 million years ago in what is now Mongolia. Because the rabbit's epiglottis is engaged over the soft palate except when swallowing, the rabbit is an obligate nasal breather. As lagomorphs, rabbits have two sets of incisor teeth, one behind the other, a manner in which they differ from rodents, which only have one set of incisors. Another difference is that for rabbits, all of their teeth continue to grow, whereas for most rodents, only their incisors continue to grow. Carl Linnaeus originally grouped rabbits and rodents under the class Glires; later, they were separated as the scientific consensus is that many of their similarities were a result of convergent evolution. DNA analysis and the discovery of a common ancestor have supported the view that they share a common lineage, so rabbits and rodents are now often grouped together in the clade or superorder Glires.
Morphology
Since speed and agility are a rabbit's main defenses against predators, rabbits have large hind leg bones and well-developed musculature. Though plantigrade at rest, rabbits are on their toes while running, assuming a more digitigrade posture. Rabbits use their strong claws for digging and (along with their teeth) for defense. Each front foot has four toes plus a dewclaw. Each hind foot has four toes (but no dewclaw).
Most wild rabbits (especially compared to hares) have relatively full, egg-shaped bodies. The soft coat of the wild rabbit is agouti in coloration (or, rarely, melanistic), which aids in camouflage. The tail of the rabbit (with the exception of the cottontail species) is dark on top and white below. Cottontails have white on the top of their tails.