Black-tailed Jackrabbit

Taxobox
name = Black-tailed JackrabbitMSW3 Hoffmann | pages = 196]
status = LR/lc | status_system = IUCN2.3
status_ref = IUCN2006 | assessors = Lagomorph Specialist Group | year = 1996 | id = 41276 | title = Lepus californicus | downloaded = 2006-05-06 Database entry includes a brief justification of why this species is of least concern]


image_width = 240px
regnum = Animalia
phylum = Chordata
classis = Mammalia
ordo = Lagomorpha
familia = Leporidae
genus = "Lepus"
species = "L. californicus"
binomial = "Lepus californicus"
binomial_authority = Gray, 1837The Black-tailed Jackrabbit ("Lepus californicus"), also known as the Desert Hare, is a common hare of the western United States and Mexico, where it is found at elevations from sea level to up to 10,000 feet (3000 m).

Like other jackrabbits, the Blacktail has distinctive long ears, and the long, powerful rear legs characteristic of hares. Reaching a length of about two feet (60 cm), and a weight from three to six pounds (1.5 to 3 kg), the Black-tailed Jackrabbit is the third largest North American hare, second only to the Antelope Jackrabbit and the White-tailed Jackrabbit. The Black-tailed Jackrabbit's dorsal fur is agouti (dark buff peppered with black), and its undersides and the insides of its legs are creamy white. The ears are black-tipped on the outer surface, and unpigmented inside. The ventral surface of the tail is grey to white, and the black dorsal surface of the tail continues up the spine for a few inches to form a short, black stripe.

The Black-tailed Jackrabbit is a natural denizen of desert, prairie and chaparral communities, though it also commonly feeds in cultivated pastures and lawns. It may be seen during the day, though it is predominantly crepuscular and nocturnal in its habits. Diet includes cactus, sagebrush, mesquite, juniper berries, grasses, and crop plants such as clover and alfalfa. The hares drink very little, deriving most of their water from their food. Like most hares, Black-tailed Jackrabbits do not use burrows, but rest during the day in a shallow scrape, called a "form," dug into the soil and usually under the cover of available vegetation.

Black-tailed Jackrabbits rely on their acute hearing and speed and to evade predators. They can reach speeds of up to 40–45 mph (64–72 km/h), and can leap 19 feet (6 m) in a single bound. Their natural predators include Red-tailed Hawks, Ferruginous Hawks, and eagles, as well as mammalian carnivores such as coyotes, foxes, and bobcats.

Although they are generally solitary animals, Blacktails often forage and rest in groups, each individual relying on the eyes and ears of the others to detect predators. Like some other lagomorphs, such as the European Rabbit, jackrabbits will thump the ground with their hind legs as an alarm signal as they sprint away from perceived danger.

Breeding can occur year-round in the southern regions of the species' range. In the wild, females (does) rarely breed before the age of one year, although they are fertile before that age. A healthy doe may produce four to five litters per year, with one to eight young per litter. Wild leverets usually weigh between 80–100 grams (2–3 ounces) at birth, although healthy, well-fed captive individuals are known to have given birth to young as large as 155 grams (5.5 ounces). A doe usually gives birth to her offspring in a form or close to thick brush, and if there are multiple leverets in a litter, she will usually not leave them in a single location. This may be an evolutionary adaptation that prevents a predator from devouring an entire litter. Gestation lasts 45 days, and although the young are precocial, (i.e., active and relatively independent from birth), the mother hare will nurse her babies for a full 12 weeks before weaning them.

Black-tailed Jackrabbit populations may undergo "boom-bust" cycles which can be quite localized: the animals may be plentiful in one valley and almost absent from an adjacent valley. Population crashes occur mostly in response to disease (especially Tularemia), although environmental factors such as food availability also can affect population structure. These cycles may contribute to similar fluctuations in mammalian predator populations, such as coyotes, and may affect the numbers of transient migratory avian predators. Because Black-tailed Jackrabbits reproduce relatively rapidly, the population usually recovers quickly after a crash, given suitable environmental conditions.

The high prevalence of disease and parasites in wild jackrabbits also affects human predation. Many hunters will not collect the jackrabbits they shoot, and those that do are well-advised to wear gloves while handling carcasses and to cook the meat thoroughly to avoid contracting Tularemia. Most hunting of jackrabbits is done for "pest" control or sport.

There are six subspecies of this jackrabbit:
*"Lepus californicus californicus"
*"Lepus californicus deserticola"
*"Lepus californicus insularis"
*"Lepus californicus madalenae"
*"Lepus californicus melanotis"
*"Lepus californicus texianus"

Gallery

References

External links

*ITIS|ID=180115|taxon=Lepus californicus|year=2006|date=23 March