Lepus alleni

Geographic Range

Lepus alleni , the antelope jackrabbit, is found mostly along the western coast of Mexico, but also in southern Arizona in the United States. In Mexico, antelope jackrabbits inhabit the Mexican states adjacent to the Gulf of California and the Pacific Ocean: Sonora, Sinaloa, and northern Nayarit. In Arizona, antelope jackrabbits inhabit a small southern area, mostly in the Sonoran desert. Lepus alleni is also located on Tiburon, a small island off the coast of the Mexican state of Sonora.

• Biogeographic Regions
• nearctic nearctic
  • native native

Habitat

In Arizona, antelope jackrabbits inhabit grassy slopes at moderate elevations. They are most commonly found in areas where grass grows well under desert shrubs that are moderately high and open. They are less common in creosote bush desert and in the low parts of valleys with dense mesquite stands. In Mexico, antelope jackrabbits prefers grasslands that are open and low, as well as foothills with patchy, low bushes and grass. They are most common in the foothills near the coast.

• Habitat Regions
• temperate temperate
• terrestrial terrestrial

• Terrestrial Biomes
• desert or dune desert or dune
• savanna or grassland savanna or grassland
• chaparral chaparral

• Other Habitat Features
• agricultural agricultural

Physical Description

Size is the most distinctive trait of Lepus alleni ; it is a large Lepus species, with the head and ears being especially large. Their ears are tall (on average 162mm long) and mostly devoid of hair except for fringes of white hair along the edges and on the tips. The side of the body (limbs, hips, rump) are white haired with black tips. The ventral surface (chin, throat, stomach, insides of limbs) are all white haired as well as the tail. The rest of the body (upper part) is yellow/brown with some black.

Lepus alleni deals with seasonality by adjusting its basal metabolic rate. It increases by 15% during the winter compared to the summer.

Antelope jackrabbits have many ways of dealing with heat. The fur is highly reflective and insulated, which helps to eliminate heat gain from the environment. Antelope jackrabbits can reduce blood flow to their large ears, which reduces heat exchanger. When not able to find shelter, Lepus alleni can tolerate heat stress at high levels better and for a longer time than Lepus californicus .

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• sexes alike

Reproduction

Only 2 copulations have been observed, so mating behavior is not well known for Lepus alleni . Both copulations were characterized by an aggressive female: one was aggressive afterwards, growling and chasing the male away and the other female growled and fought with the male before mating.

Antelope jackrabbit males will fight by boxing. They stand on their hind feet, using their forelimbs to strike each other repeatedly and rapidly for several seconds. This exchange is usually quiet and the fight ends when the winner chases the loser away. Fights can be serious enough to wound a jackrabbit badly, including torn ears, cuts, and even rare injuries such as one case where a male lost the paw of its forelimb. Male on male fighting is likely to be related to competition for females, but the mating system is not well known.

• Mating System
• polygynandrous (promiscuous) polygynandrous (promiscuous)

The gestation period for a female is about 6 weeks, with an average of 2 young per litter. Litter sizes range from 1 to 5 young. Females can have 3 or 4 litters each year. Like most hares ( Lepus ), antelope jackrabbit young are born well-developed and are weaned and independent just a few days after birth, exact numbers are not given in the literature. By 5 days old the young have well-developed incisors and are covered in short fur. Young are not born with the characteristic white rump, but the rump flash can be displayed at as young as 19 days if the young antelope jackrabbit is alarmed.

• Key Reproductive Features
• iteroparous iteroparous
• year-round breeding year-round breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• viviparous viviparous

It is thought that female antelope jackrabbits scatter their young in different hiding places after birth, and return to feed the young at night. There are no indications of burrows made by mothers for their young, but there are a few instances of well concealed "nests." One nest was concealed under some beargrass, another under a mesquite near sacaton grass and one was even in a hollowed-out barrel cactus shell. Females invest heavily in the development of their young during gestation, giving birth to precocial young that are independent just a few days after their birth. Male antelope jackrabbits do not contribute to the care of their young.

• Parental Investment
• precocial precocial
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female

Lifespan/Longevity

Not much is known about the lifespan of antelope jackrabbits as they are hard to keep alive in captivity and they are difficult to capture and study in the wild.

Behavior

Lepus alleni is crepuscular and nocturnal, although they may be active during the day on cloudy days. Antelope jackrabbits spend their days in the hot season staying out of the sun in what are called "shelter forms." These are created by backing up under grass, weeds or brush, or just sitting in the shade of a cactus or mesquite trunk; though they preferentially choose mesquite and creosote bush. These forms help with the extreme heat during the day. Since leporids are coprophagic, forms might also help with the re-digestion of pellets, by making it safer to sit and digest. Like other jackrabbits, antelope jackrabbits are solitary.

• Key Behaviors
• cursorial
• terricolous
• saltatorial saltatorial
• nocturnal nocturnal
• crepuscular crepuscular
• motile motile
• nomadic nomadic
• sedentary sedentary
• daily torpor
• solitary solitary

Home Range

Home ranges in Lepus alleni have not been documented.

Communication and Perception

Antelope jackrabbits uses their long ears to listen for predators and get a sense of their surroundings. Only in rare circumstances do antelope jackrabbits use sound as a form of communication. A pheromone may be used by this species in the form of a rectal gland that secretes a strong musky odor and may be used to scent mark a shelter form.

• Communication Channels
• visual visual
• acoustic acoustic
• chemical chemical

• Other Communication Modes
• pheromones pheromones
• scent marks scent marks

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Lepus alleni is a folivore (leaf-eater), gramnivore (grass-eater) and succulent plant eater (esp. cacti). They do not actively drink water, but derive it from their diet, especially from eating cacti stems. May and June are the most arid months in their range and the rainy season occurs in July and August. In the dry season they depend mostly on mesquite leaves and cacti, but during the wet season, they switch to grass. Some minerals are derived from geophagy, but this behavior is rare.

• Primary Diet
• herbivore herbivore
  • folivore folivore

• Plant Foods
• leaves
• wood, bark, or stems

Predation

Lepus alleni is precocial at birth and ready to flee if a predator finds the mother and young soon after birth. Young are more nocturnal, less likely to leave a shelter, and generally more wary of their surroundings than are adults. Once grown, there are many predator avoidance strategies. One is to sit in a shelter form that is open on three sides, but offers protection from birds of prey. If a terrestrial predator is detected, the antelope jackrabbit can run or conceal itself in a shelter form. If it stays concealed, it will back into the shelter form, lay its ears close to the body, and extend the forelimbs for a quick escape. If it decides to run, it will take to all fours and flash a white area on its rump towards the predator. As it runs away in a zig-zag pattern, it will keep a white area exposed towards the predator, in hopes of confusing it. The antelope jackrabbit will also hop like a kangaroo in tall grasses to be able to see where the predator is.

• Anti-predator Adaptations
• cryptic cryptic

Ecosystem Roles

Through their grazing, antelope jackrabbits can force habitat succession in the direction of the climax stage on a range that is moderately deteriorated. On range that has more weeds than grasses (indicating worse deterioration), their grazing may further degrade the habitat. Antelope jackrabbits are important prey for medium to large terrestrial and avian predators. Their folivory influences the composition and health of their native habitats.

Economic Importance for Humans: Positive

Antelope jackrabbits are valuable for food and their skin.

• Positive Impacts
• food food
• body parts are source of valuable material

Economic Importance for Humans: Negative

Through grazing, Lepus alleni is sometimes said to compete with domestic animals that graze on the same land. However, the impact may not be substantial as rabbits may graze in different ways and on different plants than domestic animals. In terms of quantity 15 antelope jackrabbits consume as much as 1 sheep, and 74 antelope jackrabbits consume as much as 1 domestic cow.

Conservation Status

Lepus alleni habitat in southern Arizona is threatened by Lehmann lovegrass ( Eragrostis lehmanniana ), a non-native grass species which is not edible for antelope jackrabbits. Conversion of wild land for agriculture will lead to a further decline in antelope jackrabbit populations. Human impacts on antelope jackrabbit habitat also include housing developments, livestock grazing, recreational trails, and canal building.

Other Comments

The common name antelope jackrabbit is derived from the white flashing behavior of American pronghorns ( Antilocapra americana ) when they run. Antelope jackrabbits also flash their white tails when they flee.

Lepus alleni is named after John Asaph Allen who was the Curator of the Department of Mammals and Birds at the American Museum of Natural History.

Common names include: Allen's hare, Allen's jackrabbit, blanket jack, burro jack, jackass rabbit, Mexican jackrabbit, saddle jack, and wandering jackrabbit.

Additional Links

Encyclopedia of Life

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Kristen Rosenblum (author), University of Oregon, Stephen Frost (editor, instructor), University of Oregon.

References

Best, T., T. Henry. 1993. Lepus alleni. Mammalian Species , 424: 1-8.

C.F. Brown, P. 2003. Habitat Characteristics of 3 Leproid Species in South-Eastern Arizona. The Journal Of Wildlife Management , 67: 83-89.

David S. Hinds, 1977. Acclimatization of Thermoregulation in Desert-Inhabiting Jackrabbits (Lepus Alleni and Lepus Californicus). Ecology , 58: 246-264.

Mearns, E. 1890. Description of supposed new species and subspecies of mammals from Arizona. Bulletin of the American Museum of Natural History , 2: 27-307.

Vorhies, C., W. Taylor. 1933. The life histories and ecology of jack rabbits, Lepus alleni and Lepus californicus ssp. in relation to grazing in Arizona. University of Arizona, College of Agriculture, Agricultural Experiment Station Technical Bulletin , 49: 471-587.