Rabbits and hares

Leporidae is the family of rabbits and hares, containing over 60 species of extant mammals in all. The Latin word ''Leporidae'' means "those that resemble ''lepus''" (hare). Together with the pikas, the Leporidae constitute the mammalian order Lagomorpha. Leporidae differ from pikas in that they have short, furry tails and elongated ears and hind legs.

The common name "rabbit" usually applies to all genera in the family except '' Lepus'', while members of ''Lepus'' (almost half the species) usually are called hares. Like most common names, however, the distinction does not match current taxonomy completely; jackrabbits are members of ''Lepus'', and members of the genera ''Pronolagus'' and '' Caprolagus'' sometimes are called hares.

Various countries across all continents except Antarctica and Australia have indigenous species of Leporidae. Furthermore, rabbits, most significantly the European rabbit, ''Oryctolagus cuniculus'', also have been introduced to most of Oceania and to many other islands, where they pose serious ecological and commercial threats.

Characteristics

Leporids are small to moderately sized mammals, adapted for rapid movement. They have long hind legs, with four toes on each foot, and shorter fore legs, with five toes each. The soles of their feet are hairy, to improve grip while running, and they have strong claws on all of their toes. Leporids also have distinctive, elongated and mobile ears, and they have an excellent sense of hearing. Their eyes are large, and their night vision is good, reflecting their primarily nocturnal or crepuscular mode of living.

Leporids are all roughly the same shape and fall within a small range of sizes with short tails, ranging from the 21 cm (8 in) long Tres Marias cottontail to the 76 cm (30 in) long desert hare. Female leporids are almost always larger than males, which is unusual among terrestrial mammals, in which males are usually the larger sex.

Both rabbits and hares are almost exclusively herbivorous (although some ''Lepus'' species are known to eat carrion), feeding primarily on grasses and herbs, although they also eat leaves, fruit, and seeds of various kinds. They are coprophagous, as they pass food through their digestive systems twice, first expelling it as soft green feces, called cecotropes, which they then reingest, eventually producing hard, dark fecal pellets. Like rodents, they have powerful front incisor teeth, but they also have a smaller second pair of incisors to either side of the main teeth in the upper jaw, and the structure is different from that of rodent incisors. Also like rodents, leporids lack any canine teeth, but they do have more cheek teeth than rodents do. Their jaws also contain a large diastema. The dental formula of most, though not all, leporids is:

They have adapted to a remarkable range of habitats, from desert to tundra, forests, mountains, and swampland. Rabbits generally dig permanent burrows for shelter, the exact form of which varies between species. In contrast, hares rarely dig shelters of any kind, and their bodies are more suited to fast running than to burrowing.

The gestation period in leporids varies from around 28 to 50 days, and is generally longer in the hares. This is in part because young hares, or leverets, are born fully developed, with fur and open eyes, while rabbit kits are naked and blind at birth, having the security of the burrow to protect them. Leporids can have several litters a year, which can cause their population to expand dramatically in a short time when resources are plentiful.

Reproduction

Leporids are typically polygynandrous, and have highly developed social systems. Their social hierarchies determine which males mate when the females go into estrus, which happens throughout the year. Gestation periods are variable, but in general, higher latitudes correspond to shorter gestation periods. Moreover, the gestation time and litter size correspond to predation rates as well. Species nesting below ground tend to have lower predation rates and have larger litters.

Evolution

The oldest known leporid species date from the late Eocene, by which time the family was already present in both North America and Asia. Over the course of their evolution, this group has become increasingly adapted to lives of fast running and leaping. For example, ''Palaeolagus'', an extinct rabbit from the Oligocene of North America, had shorter hind legs than modern forms (indicating it ran rather than hopped) though it was in most other respects quite rabbit-like. Two as yet unnamed fossil finds—dated ~48 Ma (from China) and ~53 Ma ( India)—while primitive, display the characteristic leporid ankle, thus pushing the divergence of Ochotonidae and Leporidae yet further into the past.

The cladogram is from Matthee et al., 2004, based on nuclear and mitochondrial gene analysis.

Classification

Family Leporidae: rabbits and hares
* Genus '' Pentalagus''
** Amami rabbit, ''Pentalagus furnessi''
* Genus '' Bunolagus''
** Riverine rabbit, ''Bunolagus monticularis''
* Genus ''Nesolagus''
** Sumatran striped rabbit, ''Nesolagus netscheri''
** Annamite striped rabbit, ''Nesolagus timminsi''
* Genus '' Romerolagus''
** Volcano rabbit, ''Romerolagus diazi''
* Genus '' Brachylagus''
** Pygmy rabbit, ''Brachylagus idahoensis''
* Genus '' Sylvilagus''
** Subgenus ''Tapeti''
*** Swamp rabbit, ''Sylvilagus aquaticus''
***Andean tapetí, ''Sylvilagus andinus''
*** Bogota tapetí, ''Sylvilagus apollinaris''
***Ecuadorian tapetí, ''Sylvilagus daulensis''
*** Common tapetí, ''Sylvilagus brasiliensis''
***Fulvous tapetí, ''Sylvilagus fulvescens''
*** Dice's cottontail, ''Sylvilagus dicei''
***Central American tapetí, ''Sylvilagus gabbi''
***Northern tapetí, ''Sylvilagus incitatus''
*** Omilteme cottontail, ''Sylvilagus insonus''
*** Nicefor's tapetí, ''Sylvilagus nicefori''
***Marsh rabbit, ''Sylvilagus palustris''
***Suriname tapetí, ''Sylvilagus parentum''
***Colombian tapetí, ''Sylvilagus salentus''
***Santa Marta tapetí, ''Sylvilagus sanctaemartae''
***Western tapetí, ''Sylvilagus surdaster''
***Coastal tapetí, ''Sylvilagus tapetillus''
*** Venezuelan lowland rabbit, ''Sylvilagus varynaensis''
** Subgenus '' Sylvilagus''
*** Desert cottontail, ''Sylvilagus audubonii''
*** Mexican cottontail, ''Sylvilagus cunicularis''
*** Eastern cottontail, ''Sylvilagus floridanus''
*** Tres Marias cottontail, ''Sylvilagus graysoni''
***Robust cottontail, ''Sylvilagus holzneri''
*** Mountain cottontail, ''Sylvilagus nuttallii''
*** Appalachian cottontail, ''Sylvilagus obscurus''
*** New England cottontail, ''Sylvilagus transitionalis''
** Subgenus ''Microlagus''
*** Brush rabbit, ''Sylvilagus bachmani''
* Genus ''Oryctolagus''
** European rabbit, ''Oryctolagus cuniculus''
* 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 '' Caprolagus''
** Hispid hare, ''Caprolagus hispidus''
* Genus '' Lepus''
** Subgenus ''Macrotolagus''
*** Antelope jackrabbit, ''Lepus alleni''
** Subgenus ''Poecilolagus''
*** Snowshoe hare, ''Lepus americanus''
** Subgenus ''Lepus''
*** Arctic hare, ''Lepus arcticus''
*** Alaskan hare, ''Lepus othus''
*** Mountain hare, ''Lepus timidus''
** Subgenus ''Proeulagus''
*** Black jackrabbit, ''Lepus insularis''
*** Desert hare, ''Lepus tibetanus''
*** Tolai hare, ''Lepus tolai''
** Subgenus ''Eulagos''
*** Broom hare, ''Lepus castroviejoi''
*** Yunnan hare, ''Lepus comus''
*** Korean hare, ''Lepus coreanus''
*** European hare, ''Lepus europaeus''
*** Manchurian hare, ''Lepus mandshuricus''
*** Ethiopian highland hare, ''Lepus starcki''
** Subgenus ''Sabanalagus''
*** Ethiopian hare, ''Lepus fagani''
*** African savanna hare, ''Lepus victoriae''
** Subgenus ''Indolagus''
*** Hainan hare, ''Lepus hainanus''
*** Indian hare, ''Lepus nigricollis''
*** Burmese hare, ''Lepus peguensis''
** Subgenus ''Sinolagus''
***Chinese hare, ''Lepus sinensis''
** Subgenus ''Tarimolagus''
*** Yarkand hare, ''Lepus yarkandensis''
** '' Incertae sedis''
*** Tamaulipas jackrabbit, ''Lepus altamirae''
*** Japanese hare, ''Lepus brachyurus''
*** Black-tailed jackrabbit, ''Lepus californicus''
*** White-sided jackrabbit, ''Lepus callotis''
*** Cape hare, ''Lepus capensis''
*** Corsican hare, ''Lepus corsicanus''
*** Tehuantepec jackrabbit, ''Lepus flavigularis''
*** Granada hare, ''Lepus granatensis''
*** Abyssinian hare, ''Lepus habessinicus''
*** Woolly hare, ''Lepus oiostolus''
*** Scrub hare, ''Lepus saxatilis''
*** White-tailed jackrabbit, ''Lepus townsendii''
*Genus †''Serengetilagus''
** †''Serengetilagus praecapensis''
*Genus †'' Aztlanolagus''
** †''Aztlanolagus agilis''

Predation

Predators of rabbits and hares include raccoons, snakes, eagles, canids, cats, mustelids, owls and hawks. Animals that eat roadkill rabbits include vultures and buzzards.

See also

* Mara (mammal)
* Viscacha

References

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Leporidae
Mammal families
Extant Ypresian first appearances
Taxa named by Gotthelf Fischer von Waldheim