Rabbits and Hares - biology.

Rabbits and Hares - biology. I INTRODUCTION Rabbits and Hares, common name for certain small, furry mammals with long ears and short tails. Although the names rabbit and hare are often used interchangeably, in zoological classification the species called rabbits are characterized by the helplessness of their offspring, which are born naked and with closed eyes, and by their gregarious habit of living in colonies in underground burrows. (The exception is the cottontail of North America, which does not dig burrows; its nest is on the surface, usually in dense vegetation, and it is not social.) Species designated zoologically as hares are born furred and with open eyes, and the adults merely construct a simple nest and rarely live socially. Furthermore, the hare is generally larger than the rabbit and has longer ears with characteristic black markings. Moreover, the skulls of rabbits and hares are distinctly different. Distributed throughout the world, hares and rabbits have many common characteristics. Both groups breed prolifically, bearing four to eight litters a year, with three to eight young in each litter, have a period of gestation lasting about a month, reach sexual maturity in about six months, and have a life span of about ten years. These animals, which weigh from about 1 to 5 kg (about 2 to 11 lb) and attain a length of about 30 to 60 cm (about 12 to 24 in), feed mainly on herbs, tree bark, and vegetables. They prefer to live in regions where the soil is loose and dry and where brushwood offers shelter. Although rabbits and hares are valued as game by hunters, as food, and for their fur, they often are pests to farmers whose trees and crops they destroy. The species commonly found in the United States are the cottontail, the snowshoe rabbit, the jackrabbit, and the domestic rabbit. II COTTONTAIL The chief wild rabbit of North America is the cottontail. Its name is derived from the white undersurface of its short tail, which resembles a puff of cotton. The cottontail is noted for remaining motionless to avoid notice when it senses danger. The rabbit, which swims well, also evades enemies by plunging into lakes or streams. III SNOWSHOE The varying hare, known popularly as the snowshoe rabbit, is distributed widely throughout North America. In winter it is pure white except for black ear tips, and in summer it is reddish-brown. The young snowshoe weighs 85 g (3 oz) at birth and develops so rapidly that it crawls on the second day after birth and hops on the third day. Adult males, called bucks, fight one another with their teeth when they court the same females, which are known as does. Although largely herbivorous, the adult snowshoe rabbit may eat mice and carrion. IV JACKRABBIT One species of jackrabbit, the black-tailed jackrabbit, is found in the western parts of the United States and Canada. The fastest of the rabbits and hares, jackrabbits achieve speeds of about 70 km/h (about 45 mph) and can bound some 4.5 to 6 m (some 15 to 20 ft) in a single jump. Because this species competes with grazing animals for food, livestock owners in the western United States have undertaken great drives to reduce the hare population, which has been estimated to be as high as 3,100 per sq km (8,000 per sq mi). Jackrabbits may carry tularemia, a bacterial disease that can be fatal to humans. V DOMESTIC RABBIT At least 66 varieties of the domesticated rabbit are derived from a wild rabbit native to Europe and Africa. Some varieties are Angora, Belgian, Dutch, Himalayan, lop, Siberian, Patagonian, silver-tip, Polish, and Flemish. The domesticated rabbit has extremely diverse characteristics, varying in color through every grade, shade, and mixture, from pure white to all black; in coat from very short to long, silky hair capable of being woven; and in style of ears from the prick ear--erect, small and almost as stiff as metal--to the floppy, broad, soft-skinned lopped ear, which hangs to the ground. Domestic rabbits warn one another of danger by thumping on the ground with their hind feet. They are bred as pets, for genetic studies, for laboratory experimentation, and for their meat and furs; domestic rabbits' furs are sold under the trade names of arctic seal, clipped seal, and lapin. Rabbits have been introduced to South America, Java, Australia, New Zealand, and various oceanic islands around the world. A significant instance of the rapid distribution of rabbits can be found in the present abundance of rabbits in Australia and New Zealand. In New Zealand, seven rabbits were first turned out near Invercargill, apparently about 1860. They soon spread to both countries and multiplied so rapidly that rabbit control became a serious problem. In Australia a virus deadly only to true rabbits was developed, and in 1951 decimation of the rabbit population began through the artificial promotion of this virus infection, known as myxomatosis. The project met with success only in areas with sufficient water to serve as breeding grounds for mosquitoes, which transmit the virus. However, the disease spread to Europe, killing rabbits in Britain, Belgium, and France, where the animal serves useful purposes. VI RABBITS AS PETS Rabbits are often kept as pets. Pet rabbits are inquisitive, social animals that often form strong bonds with humans as well as with other domestic animals such as guinea pigs, cats, and sometimes birds and dogs. Pet rabbits may be housed in an outdoor cage or fenced enclosure, but providing an outdoor rabbit with sufficient companionship, space to run and jump, and protection from predators can be difficult. As a result, many experts recommend keeping rabbits indoors as house pets. A rabbit living in the home of its owner is called a house rabbit. House rabbits can live 7 to 12 years with proper care, which includes regular exercise, frequent social interaction with people or other house pets, a diet rich in timothy hay, and medical care from a veterinarian who specializes in exotic animals. Like cats, most rabbits can easily learn to use a litter box and may be allowed to roam freely throughout a designated part of the house. Unlike cats, however, rabbits have continuously growing teeth and are naturally inclined to nibble on hard objects, including books, furniture, and dangerous items such as electrical cords. Before introducing a rabbit to a room, it is very important to remove dangerous or valuable objects that might be within the rabbit's reach. This process is commonly called rabbit proofing. Guidelines for rabbit proofing a home are often included in books on house rabbit care and are available from many veterinarians and rabbit rescue organizations. Scientific classification: Rabbits and hares belong to the family Leporidae of the order Lagomorpha. Cottontails are classified in the genus Sylvilagus. The snowshoe rabbit is classified as Lepus americanus, the black-tailed jackrabbit as Lepus californicus, and the wild rabbit of Europe and Africa as Oryctolagus cuniculus. Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corporation. All rights reserved.