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Lepus californicusblack-tailed jackrabbit

By Liz Ballenger

Ge­o­graphic Range

Lepus cal­i­for­ni­cus is found through­out the south­west­ern United States into Mex­ico, as far east as Mis­souri, north into Wash­ing­ton, Idaho, Col­orado and Ne­braska, and west to Cal­i­for­nia and Baja Cal­i­for­nia.

Habi­tat

Black-tailed jackrab­bits in­habit desert scrub­land, prairies, farm­lands, and dunes. They favor arid re­gions and areas of short grass range­land from sea level to about 3,800 m. Many dif­fer­ent veg­e­ta­tion types are used, in­clud­ing sage­brush-cre­osote bush, mesquite-snake­weed and ju­niper-big sage­brush. They also fre­quent agri­cul­tural areas where they can im­pact fruit and grain crops.

  • Range elevation
    3800 (high) m
    12467.19 (high) ft

Phys­i­cal De­scrip­tion

Black-tailed jackrab­bits mea­sure 47-63 cm from nose to rump, the tail is be­tween 50-112 mm and the ears are 10-13 cm long. As they are true hares, black-tailed jackrab­bits are lankier and leaner than rab­bits, have longer ears and legs, and the lev­erets are born fully-furred and open-eyed. Black-tailed jackrab­bits pos­sess a char­ac­ter­is­tic black stripe down the cen­ter of the back, a black rump patch, and the tail is black dor­sally. Both sexes look alike, but the fe­male is the larger of the two sexes.

  • Sexual Dimorphism
  • female larger
  • Range mass
    1.3 to 3.1 kg
    2.86 to 6.83 lb
  • Range length
    47 to 63 cm
    18.50 to 24.80 in
  • Average basal metabolic rate
    7.314 W
    AnAge

Re­pro­duc­tion

Black-tailed jackrab­bit males and fe­males leap after, chase, and be­have ag­gres­sively to­wards each other dur­ing a brief courtship phase be­fore mat­ing.

Breed­ing sea­son for Lepus cal­i­for­ni­cus ex­tends from De­cem­ber through Sep­tem­ber in Ari­zona and from late Jan­u­ary to Au­gust in Cal­i­for­nia and Kansas. Fe­males pro­duce 3 or 4 lit­ters an­nu­ally with 1-6 lev­erets (gen­er­ally 3 or 4) after a 41-47 day ges­ta­tion pe­riod. The young are pre­co­cial; fe­males only nurse their off­spring for 2-3 days and are not seen with their young after that time. Lifes­pan in cap­tiv­ity is 5-6 years, but rab­bits in the wild often die much sooner due to pre­da­tion, dis­ease or prob­lems as­so­ci­ated with over­pop­u­la­tion.

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • sexual
  • Range number of offspring
    1 to 8
  • Average number of offspring
    2.26
  • Average number of offspring
    1
    AnAge
  • Range gestation period
    41 to 47 days
  • Average gestation period
    43 days
  • Range weaning age
    14 to 21 days
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    243 days
    AnAge

Lifes­pan/Longevity

Be­hav­ior

As with all hares, black­tails rely on speed and cam­ou­flage (along with the char­ac­ter­is­tic "freeze" be­hav­ior) for their de­fense. When flushed from cover, a black­tail can spring 20 feet at a bound and reach top speeds of 30-35 mph over a zigzag course. Black-tailed jackrab­bits do not gen­er­ally oc­cupy bur­rows: rather, they dig shal­low de­pres­sions in the earth in which to lay. Black-tailed jackrab­bits are mainly unso­cia­ble but are dri­ven to com­mon food sources in pe­ri­ods of drought. They are in­ac­tive dur­ing the hot af­ter­noon hours and are mainly noc­tur­nal, rest­ing under bushes by day. Home ranges in Cal­i­for­nia av­er­age 20ha (de­pen­dent upon pop­u­la­tion den­sity), with fe­males hav­ing larger ranges than males.

Com­mu­ni­ca­tion and Per­cep­tion

Food Habits

Grasses and herba­ceous mat­ter are the pre­ferred foods of Lepus cal­i­for­ni­cus, but twigs and young bark of woody plants are the sta­ple food when other plants are not avail­able. Sage­brush and cacti are also taken. Jackrab­bits eat al­most con­stantly and con­sume large quan­ti­ties rel­a­tive to their size; 15 jackrab­bits eat as much as a large graz­ing cat­tle in one day. Black-tailed jackrab­bits do not re­quire much water and ob­tain nearly all the water they need from the plant ma­te­r­ial they con­sume.

  • Plant Foods
  • leaves
  • roots and tubers
  • wood, bark, or stems
  • fruit

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

As with many other Lepus species, L. cal­i­for­ni­cus has been widely used as food for hu­mans, es­pe­cially by Na­tive Amer­i­cans. Their fur is not durable nor valu­able, but it has been ex­ten­sively used in the man­u­fac­ture of felt and as trim­ming and lin­ing for gar­ments and gloves.

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

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

Due to the re­moval of nat­ural preda­tors, such as coy­ote and kit fox, by Eu­ro­pean set­tlers, black-tailed jackrab­bit pop­u­la­tions have un­der­gone in­cred­i­ble pop­u­la­tion ex­plo­sions in which crops, or­chards, and range­lands have suf­fered. They do con­sid­er­able damange to farms, for­est plan­ta­tions, and young trees.

  • Negative Impacts
  • crop pest

Con­ser­va­tion Sta­tus

Pop­u­la­tion num­bers of black-tailed jackrab­bits are some­times quite high de­spite at­tempts at culling their pop­u­la­tions by ranch­ers and farm­ers. Pop­u­la­tion den­si­ties often reach 470 an­i­mals per square km, with den­si­ties as high as 1500 an­i­mals per square km being recorded. Large herd­ing at­tempts have net­ted as much as 6,000 hares at a time. As with many hares, Lepus cal­i­for­ni­cus pop­u­la­tions un­dergo dras­tic fluc­tu­a­tions, with pop­u­la­tion num­bers peak­ing every 6 to 10 years. In some years more then 90 per cent of west­ern pop­u­la­tions die from tu­laremia, which may or may not be re­lated to the pop­u­la­tion cy­cling phe­nom­e­non. Be­cause of their in­cred­i­ble fe­cun­dity, black-tailed jackrab­bit num­bers quickly re­cover from these kinds of die-offs.

Black-tailed jackrab­bit pop­u­la­tions are not threat­ened in gen­eral, though ex­ten­sive habi­tat de­struc­tion may re­duce suit­able habi­tat. (Wil­son and Ruff, 1999)

Other Com­ments

Jackrab­bits ob­tained their name from early set­tlers of the South­west who, not­ing the an­i­mal's ex­tra­or­di­nar­ily long ears, dubbed it "jack­ass rab­bit." This name was later short­ened to jackrab­bit. This species has 8 named sub­species. (Wil­son and Ruff, 1999)

Con­trib­u­tors

Liz Bal­lenger (au­thor), Uni­ver­sity of Michi­gan-Ann Arbor.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

agricultural

living in landscapes dominated by human agriculture.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chaparral

Found in coastal areas between 30 and 40 degrees latitude, in areas with a Mediterranean climate. Vegetation is dominated by stands of dense, spiny shrubs with tough (hard or waxy) evergreen leaves. May be maintained by periodic fire. In South America it includes the scrub ecotone between forest and paramo.

chemical

uses smells or other chemicals to communicate

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

folivore

an animal that mainly eats leaves.

food

A substance that provides both nutrients and energy to a living thing.

herbivore

An animal that eats mainly plants or parts of plants.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

suburban

living in residential areas on the outskirts of large cities or towns.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

young precocial

young are relatively well-developed when born

Ref­er­ences

Flux, J.E.C. and R. Anger­mann. 1990. The hares and jackrab­bits. In: Rab­bits, Hares and Pikas: Sta­tus Sur­vey and Con­ser­va­tion Ac­tion Plan. (J.A. Chap­man and J.E.C. Flux, eds.) In­for­ma­tion Press, Ox­ford, U.K.

Grz­imek's En­cy­clo­pe­dia of Mam­mals.

Nowak, R.M. and J.L Par­adiso. 1983. Walker's Mam­mals of the World. 4th edi­tion. John Hop­kins Uni­ver­sity Press, Bal­ti­more, MD.

Rue, L.L. 1967. Pic­to­r­ial guide to the mam­mals of North Amer­ica. Thomas Y. Crow­ell Com­pany, New York.

Wil­son, D., S. Ruff. 1999. The Smith­son­ian Book of North Amer­i­can Mam­mals. Wash­ing­ton: Smith­son­ian In­sti­tu­tion Press.

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Classification

Classification

  • Kingdom Animalia animals
  • Phylum Chordata chordates
  • Subphylum Vertebrata vertebrates
  • Class Mammalia mammals
  • Order Lagomorpha hares, pikas, and rabbits
  • Family Leporidae hares and rabbits
  • Genus Lepus common hares and jackrabbits
  • Species Lepus californicus black-tailed jackrabbit