|White-tailed jackrabbit range|
The white-tailed jackrabbit (Lepus townsendii), also known as the prairie hare and the white jack, is a species of hare found in western North America. Like all hares and rabbits, it is a member of the family Leporidae of order Lagomorpha. It is a solitary individual except where several males court a female in the breeding season. Litters of four to five young are born in a form, a shallow depression in the ground, hidden among vegetation. This jackrabbit has two described subspecies: L. townsendii townsendii and L. townsendii campanius.
The white-tailed jackrabbit is a large species of hare with an adult length of 56 to 65 centimetres (22 to 26 in) and a weight between 2.5 and 4.3 kilograms (5.5 and 9.5 lb). At the northern most extremity of its range it can be almost twice as large as in the middle of it range. In Saskatchewan rare specimens have been recorded at over 9 kg. It has distinctive large grey ears with black tips which are chestnut brown and white on the inside and the long, powerful hind legs characteristic of hares. The back, flanks and limbs are dark brown or greyish-brown and the underparts are pale grey. The tail is white with a dark central stripe above. Females are slightly larger than males. In northern populations, this hare moults in the autumn and becomes white all over except for its ears. They generally make no sound but will emit a shrill scream if they are injured or caught.
Distribution and habitat
The white-tailed jackrabbit is native to western and central parts of North America. Its range includes British Columbia, Alberta, Saskatchewan, Manitoba and Ontario in Canada and Washington, Oregon, California, Nevada, Utah, Idaho, Montana, Wyoming, Colorado, New Mexico, North Dakota, South Dakota, Nebraska, Kansas, Minnesota, Wisconsin, Iowa, Missouri and Illinois in the United States. It is found in plains and prairie and in alpine meadows with scattered coniferous trees up to an elevation of about 3,000 metres (10,000 feet) in Colorado. The white-tailed jackrabbit is slightly smaller than the black-tailed jackrabbit (Lepus californicus) and where their ranges overlap, the former tends to move to higher altitudes.
The white-tailed jackrabbit is nocturnal and lies up during the day in a form, a shallow depression in the ground hidden under vegetation, emerging at dusk to feed. There are often discernible paths leading away from the form and others among the plants at often-visited feeding sites. In winter snow, the forms are interconnecting cave-like structures. This jackrabbit is a solitary species and feeds on grasses and other green plants, including cultivated crops. During the winter its diet includes buds, twigs and bark. It tends to be more selective in its feeding habits than the black-tailed jackrabbit which disadvantages it where their ranges overlap. It has good eyesight, excellent hearing and sensitive whiskers and is probably able to detect olfactory clues as to whether another jackrabbit is ready to breed.
The breeding season is variable and depends upon latitude and environmental factors and extends from February to July in different parts of the range. Several males may compete aggressively for the attention of a female by charging at each other, leaping and jostling. Ovulation by the female takes place after copulation. The gestation period is about 42 days and in preparation for the birth, the female prepares a fur-lined nest under dense vegetation. A litter consists of up to eleven young although four or five is a more typical number. The leverets weigh about 100 grams (3.5 oz) and are precocial. They have their eyes open and are fully furred at birth and soon begin to move around. They start to forage at about two weeks old and are weaned at four weeks. They are sexually mature at about seven months but do not breed until the year after their birth.
White-tailed jackrabbits influence the composition of the turf through their selective grazing activities. They are important prey species for various mammalian predators including the red fox (Vulpes vulpes), the grey fox (Urocyon cinereoargenteus), the American badger (Taxidea taxus), the mountain lion (Puma concolor), the coyote (Canis latrans) and the bobcat (Lynx rufus). Snakes sometimes attack them and bird predators include eagles, hawks and owls. They attempt to evade detection by crouching in the vegetation where their cryptic colouration makes them difficult to observe. They may slink away but if detected, they bound away at speed, adopting a zigzag course. They can run at up to 55 kilometres (34 miles) per hour and leap up to 5 metres (16 ft). As well as being caught by animal predators, they are also hunted and eaten by humans.
The white-tailed jackrabbit is assessed as being of "Least Concern" by the IUCN in its Red List of Threatened Species. This is because this hare has an extensive range and is fairly common across most of this range. The population size may be declining slightly but not at a rate that would justify listing this hare in a more threatened category.
In Wyoming however, it has become scarce in Grand Teton National Park where it has not been seen recently. Briefly reputed to have been extirpated in Yellowstone National Park where it was at one time abundant, it is now clear from observations, roadkilled specimens and historical records that white-tailed jackrabbits are still present in the park. The causes of the decline in populations in Wyoming is unclear.
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