White-sided jackrabbit  (Lepus callotis)

The white-sided jackrabbit is classified as Near Threatened (NT) on the IUCN Red List (1).

A large hare of North America, the white-sided jackrabbit (Lepus callotis) has a short, coarse coat of light grey fur, with large, conspicuous white patches along the flanks (3). It is similar in appearance to the black-tail jackrabbit (Lepus californicus), but may be distinguished from this species by its stockier build, more grizzled fur and large, white-tipped ears (4). 

The white-sided jackrabbit also has a black tail, with white on the underside, and a cream-buff head, mixed with black, with a whitish area on the side, around the eyes. The inner surfaces of the limbs are white and the outer surfaces are stained with buff, while the rump is separated by a black line that is largely concealed by sooty, brownish and white-tipped hairs (3). 

The white-sided jackrabbit has large ears and long limbs, which appear almost disproportionate to its body size, that together increase its body surface area to help dissipate heat (4). The female white-sided jackrabbit tends to be larger than the male (3) (5). 

There are currently two recognised subspecies of the white-sided jackrabbit: Lepus callotis gaillardia and Lepus callotis callotis (1). Lepus callotis callotis primarily differs from Lepus callotis gaillardia by a blackish hue to the fur, rather than a pale hue, and a black rather than brown nape (3).

The white-sided jackrabbit is only found in North America, where it is distributed from south-western New Mexico in the U.S. to northern Oaxaca in Mexico. In the U.S., it is found at just two locations in Hidalgo County, with a total range of just 120 square kilometres (1) (3). 

Lepus callotis gaillardi has a rather discontinuous distribution that extends from south-western New Mexico to north-central Mexico, while Lepus callotis callotis is distributed from the central part of east Durango toward the plains of the central part of Mexico (1).

The white-sided jackrabbit inhabits open grasslands on high-altitude, level plains. It typically avoids hill areas with trees and shrubs, preferring level lands full of grasses. In Queretaro, Mexico, the white-sided jackrabbit is found on cultivated lands, while in western Sonora, Mexico, it occurs on true desert, where it frequents bushy watercourses (1) (6).

A strictly nocturnal species, during the day the white-sided jackrabbit shelters in depressions in the ground known as ‘forms’, which are usually constructed in clumps of grass (4). It rarely occupies underground shelters (5). Over 90 percent of the white-sided jackrabbit’s diet consists of grasses and sedges (2), such as tabosa, buffalo grass, and blue grama (4). 

When startled by a predator, such as an eagle, hawk, owl, fox or coyote, the white-sided jackrabbit leaps straight upwards, while extending the hind legs and flashing its white parts. To escape, it makes rather long, high leaps, alternately flashing its white sides as it runs away. The long hind legs are highly adapted for speed, giving the white-sided jackrabbit lift, and enabling it to escape in a zigzag fashion that surpasses its predators (5). 

A monogamous species that mates for life, the white-sided jackrabbit is often seen in male-female pairs, with the male defending the pair from other males. The breeding season, which lasts for a minimum 18 weeks (3), varies from the middle of April to August (1). Usually two young are born each season, but during periods of favourable weather, the white-sided jackrabbit may attempt to rear up to three litters in a year (1). The young are born with a soft woolly coat, and attain sexual maturity at a rapid rate, breeding at just over a year old (5).

In the U.S., the white-sided jackrabbit has suffered a substantial population decline. In part, this is the result of habitat loss from overgrazing by livestock and the suppression of natural wildfires (1), which would normally prevent bushes establishing in this species’ largely barren habitat (7). Between 1976 and 1981, the white-sided jackrabbit population in New Mexico and neighbouring Durango, Mexico declined by 50 percent, with the total population then estimated at just 340 individuals. Surveys of this population between 1990 and 1995 counted less than five white-sided jackrabbits per year (1) (8). 

The decline of the white-sided jackrabbit in both the U.S. and Mexico has been accompanied by the expansion of the black-tail jackrabbit, which has adapted well to habitat change and can outcompete the white-sided jackrabbit, causing further declines (1). 

Additional threats to the white-sided jackrabbit include hunting for sport and local subsistence, human disturbance and predation by introduced animals (1). There are probably more jackrabbits killed for food in Mexico than any other game mammal (6). Global climate change has been identified as a further threat to this species, as the frequency of drought is expected to increase (1), leading to bushes and other unfavourable vegetation encroaching upon this species’ habitat (8). Up to 60 percent of the white-sided jackrabbit’s habitat is expected to be lost by 2050 due to climate change, with northern parts of its range being most severely affected (1).

In 1975, the rapid demise of the white-sided jackrabbit was recognised by its listing as Threatened by the New Mexico Department of Game and Fish. As a result, this species became the focus of increased conservation efforts, including measures to monitor its population status and trends, as well as measures to encourage shrub control and prevent detrimental grazing practices by local landowners (1). 

Further recommended conservation priorities for the white-sided jackrabbit include research to determine population numbers and range, as well as further monitoring efforts to establish trends (1).

Find out more about conservation in the U.S:

• Nature Conservancy:
  http://www.nature.org/
• U.S. Fish and Wildlife Service Home:
  http://www.fws.gov/
• Natural Resources Conservation Service:
  http://www.nrcs.usda.gov/