Jackrabbits are distinctive mammals of North America’s open landscapes, recognizable by their unique physical characteristics. Despite their common name, jackrabbits are hares belonging to the genus Lepus, not true rabbits. Their young are born fully furred, with eyes open, and are mobile shortly after birth. This physical description focuses on the traits that set these swift, open-country dwellers apart.
General Body Dimensions and Build
Jackrabbits are the largest lagomorphs within their range, possessing a lean and elongated body structure. This streamlined build is an adaptation for speed and endurance, allowing them to traverse open habitats effectively. An adult jackrabbit typically measures between 18 and 28 inches (46 to 71 cm) from nose to rump.
The weight of these animals varies by species and season, generally ranging from 3 to 9.5 pounds (1.4 to 4.3 kg). Their musculature is concentrated in the hindquarters, giving them a tapered appearance. This design allows for the powerful bursts of acceleration needed to evade predators in environments with limited cover.
The Defining Features: Ears and Hind Legs
The most striking visual characteristic of the jackrabbit is its exceptionally long ears, which can measure up to 7 inches (18 cm). These thinly furred, oversized ears serve the dual purpose of enhanced hearing and thermoregulation. They are often held upright, appearing disproportionately large compared to the rest of the head.
The ears are highly vascularized, containing a network of blood vessels that help dissipate excess body heat in arid environments. This cooling feature is particularly noticeable after a sprint or on hot days when blood flow is increased. The ears’ length and constant movement provide an immediate identification cue.
The hind legs are substantially longer and far more powerful than the shorter forelegs. This disparity in limb length is responsible for the jackrabbit’s characteristic bounding gait and incredible speed. They are capable of reaching speeds up to 40 miles per hour (64 km/h) in short bursts when fleeing a threat.
Their powerful hindquarters allow them to execute impressive leaps, covering distances of up to 10 to 15 feet (3 to 4.6 m) in a single bound. The large hind feet are covered with dense fur, which provides insulation against hot desert ground and aids in traction. This combination of long, muscular legs and furry feet makes the jackrabbit a specialized runner adapted to open terrain.
Coat Color and Unique Markings
Jackrabbits exhibit cryptic coloration, meaning their fur provides camouflage against the arid and grassy landscapes they inhabit. The typical summer coat is a mixture of grayish-brown, buff, or yellowish tones, often with a “salt-and-pepper” or agouti effect due to black-tipped guard hairs. The underside, including the belly, is much lighter, ranging from pale gray to creamy white.
Specific markings vary between species and are used for identification, especially the color of the tail and ear tips. The Black-tailed Jackrabbit (Lepus californicus) is distinguished by a black stripe along its tail and prominent black ear tips. Conversely, the White-tailed Jackrabbit (Lepus townsendii) has an entirely white tail.
In northern parts of their range, some species, such as the White-tailed Jackrabbit, undergo a seasonal molt. Their coat turns nearly pure white in winter to blend with the snow. Even in this winter phase, the tips of the ears often retain some darker coloration.