The common name “jackrabbit” often causes confusion because it does not reflect the animal’s true biological relationship. Despite its name, the jackrabbit is not a true rabbit; it is a hare. Hares and true rabbits belong to the same family, Leporidae, but they represent distinct evolutionary paths separated by differences in anatomy, behavior, and reproductive strategies. These distinctions reveal two separate survival strategies: one built around hidden security and the other around open-field speed.
Jackrabbits are Hares: Scientific Classification
All rabbits and hares belong to the mammalian order Lagomorpha, a group distinguished by a second, smaller pair of incisors located behind the first pair in the upper jaw. Within this order, they diverge into different genera that define their true biological identities. True rabbits, such as the European rabbit, generally fall under the genus Oryctolagus or related genera like Sylvilagus (cottontails). Hares, including all species of jackrabbit—like the Black-tailed Jackrabbit and White-tailed Jackrabbit—are classified under the genus Lepus.
The name “jackrabbit” originated from the descriptive term “jackass rabbit,” given due to the animal’s notably long ears. This common name is purely descriptive and does not align with its scientific designation as a hare. Jackrabbits are members of the Lepus genus, making them true hares, a distinction based on genetics and a suite of physical and behavioral traits. The division between the genera Lepus and Oryctolagus represents a significant evolutionary split.
The Crucial Distinction: State of Offspring at Birth
The most significant biological difference between hares and true rabbits lies in the developmental state of their young at birth, categorized as precocial versus altricial. Hares, including jackrabbits, give birth to precocial young, often called leverets. These newborns arrive fully furred, with their eyes open, and capable of movement within minutes of birth.
This independence allows the leverets to be hidden in a shallow depression on the ground, called a “form,” rather than an elaborate nest. The female hare minimizes attracting predators by returning only briefly to nurse them. Conversely, true rabbits are born altricial, meaning their young, called kits or kittens, are underdeveloped.
Rabbit kits are born blind, hairless, and completely helpless, unable to regulate their own body temperature. This vulnerability necessitates parental care and the construction of a secure, lined nest, typically located deep within an underground burrow system known as a warren. The contrast in offspring development reflects the differing survival strategies, with hares relying on early mobility and rabbits on protective seclusion.
Physical Anatomy and Habitat Differences
Hares and rabbits exhibit distinct anatomical differences, each adapted to a unique lifestyle and habitat. Hares, such as jackrabbits, are generally larger and have a leaner body structure compared to the more compact frame of a true rabbit. Their most recognizable feature is their disproportionately long ears, which can reach up to eight inches in length in some jackrabbit species.
These large ears function both for enhanced hearing and as a thermoregulatory adaptation. Hares circulate blood through the thin tissue of the ears to dissipate excess heat, which is essential for survival in the arid and semi-arid environments they inhabit. Their hind legs are substantially longer and more powerful than those of rabbits, optimized for explosive speed and sustained running across open terrain.
Jackrabbits can reach speeds up to 40 miles per hour, using their speed and a characteristic zigzag pattern to evade predators in habitats like open plains and desert scrub. True rabbits, by contrast, possess shorter legs and ears, better suited for quick, darting movements near cover and within dense vegetation. They rely on the extensive network of underground burrows for safety, while hares live above ground, seeking cover in shallow forms or under bushes.