Leporidae (Fischer, 1817)
* Leporidae on Mammal species of the World.
Leporids are the approximately 50 species of rabbits and hares which form the family Leporidae. The leporids, together with the pikas, constitute the mammalian order Lagomorpha. Leporids differ from pikas in having short furry tails, and elongated ears and hind legs. The name leporid is simply an abbreviation of the family name Leporidae meaning animals resembling "lepus", Latin for hare.
Members of all genera except Lepus are usually referred to as rabbits, while members of Lepus (which accounts for almost half the species) are usually called hares. However the distinction between these two common names does not map completely into current taxonomy, since jackrabbits are members of Lepus, and members of the genera Pronolagus and Caprolagus are sometimes called hares.
Leporids are native across the world except Antarctica, and in Oceania where their introduction is a significant threat for the native mammals in Australia.
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 range in size from the Pygmy Rabbit (Brachylagus idahoensis), with a head and body length of 25–29 cm, and a weight of around 300 grams, to the European Hare (Lepus europaeus), which is 50–76 cm in head-body length, and weighs from 2.5 to 5 kilograms.
Both rabbits and hares are almost exclusively herbivorous (with exceptions among the members of Lepus), 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, which they then re-ingest, 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 jaw also contains a large diastema. The dental formula of most, though not all, leporids is: Upper: 184.108.40.206, lower: 220.127.116.11
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 period of time when resources are plentiful.
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.
Family Leporidae: rabbits and hares
^ a b Hoffman, Robert S.; Smith, Andrew T. (16 November 2005). "Order Lagomorpha (pp. 185-211". In Wilson, Don E., and Reeder, DeeAnn M., eds. Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Baltimore: Johns Hopkins University Press, 2 vols. (2142 pp.). pp. 194–211. ISBN 978-0-8018-8221-0. OCLC 62265494.
Source: Wikipedia, Wikispecies: All text is available under the terms of the GNU Free Documentation License