The Black-tailed Jackrabbit (Lepus californicus) is the common hare of the western United States and Mexico, found at elevations of up to 3000 m.

Like other jackrabbits, the Black-tailed Jackrabbit has unmistakable long ears, and the long powerful rear legs characteristic of hares. Its fur is dark buff peppered with black. Its ears are tipped with black, and it has a black stripe down its back. The tail is black above but white beneath. It is the largest North American hare, reaching a length of about 60 cm, and adults weight between 1.5 and 4 kg.

The Black-tailed Jackrabbit is commonly seen on pasture and waste land during the day, though it is predominantly nocturnal in its habits. It feeds on cactus, sagebrush, mesquite, grasses, and crop plants such as clover and alfalfa. They drink little, deriving water from their food. Like most hares, Black-tailed Jackrabbits do not use burrows, but rest during the day in a scrape in the pasture called a form, relying on their acute hearing and speed to evade predators. They can reach speeds of up to 55 km/h, and can leap 6 m in a single bound. Their predators include birds of prey and mammalian carnivores as coyotes, foxes, bobcats and weasels. Although they are largely solitary animals, the white underside of the tail of a fleeing jackrabbit probably serves as a warning signal to other members of the species; jackrabbits will also thump the ground with their hind legs as an alarm signal.

Breeding can occur year-round in the south of the species' range. Up to four litters may be produced in a year, with up to eight young in a litter. They are born in a form, above ground. Gestation is long (around 45 days) and the young are precocial, i.e. they are active and relatively independent from birth, and their mothers only nurse them for a short time.

Removal of predators by humans has led to rapid increase of jackrabbit populations in some areas, and population crashes sometimes result. However, their rapid breeding means that numbers recover quickly following a crash.

Jackrabbits are on occasion hunted, but often not on a consistent basis as their population in a given area is very variable. This appears due to population fluctuation as well as migration over moderate distances in response to food and climactic factors.