The black-tailed jack rabbit (Lepus californicus) is geographically distributed throughout the western United States and Mexico (Hutchins et al., 2003; Desmond, 2004). The species is nocturnal (Hutchins et al., 2003; Desmond, 2004) and inhabits desert scrublands and prairies (Hutchins et al., 2003). Their diet consists mostly of grasses although sometimes young bark is eaten (Hutchins et al., 2003). Individuals vary in length from 47 cm to 63 cm and have ears that are 10 cm to 13 cm in length. The typical weight for the species is between 1 kg and 3 kg. The black-tailed jack rabbit is distinguished by a long black stripe that runs down its back and a black tail (Hutchins et al., 2003).
The genus Lepus includes all hares, sometimes referred to as jack rabbits. In total there are 23 species within the genus. They are characterized by having long arms and large hind feet. Females are typically larger than males, unlike many other mammalian species. They inhabit grassy areas and do not burrow. However, they will dig shallow pits to rest. In order to escape from predators, most species rely on their fast running ability (Nowak, 1991).
In many species individuals remain solitary except during mating. During the mating season, males will fight one another by “boxing” with their front paws and kicking with their hindlegs (Nowak, 1991). Females have a 30-42 day gestation period (Anderson and Jones, 1984). Young are born precocial; they have fur and are able to move on their own a few hours after birth (Nowak, 1991).
Breeding occurs throughout most of the year in the black-tailed jack rabbit. The mating season lasts from December to September and females come into estrus multiple times (Hutchins et al., 2003; Portales, 2004). Females can have between three and six litters each breeding season with up to six young in each litter (Portales, 2004).
Additional Information on the Skull
Click on the thumbnails below for labeled images of the skull in standard anatomical views.
About the Species
This specimen (TMM M-7500) was made available to the University of Texas High-Resolution X-ray CT Facility for scanning by Tim Rowe of the University of Texas. Funding for scanning was provided by a National Science Foundation Digital Libraries Initiative grant to Dr. Rowe.
About this Specimen
The specimen was scanned by Matthew Colbert on 5 January 2005 along the coronal axis for a total of 660 slices, each slice 0.1439 mm thick with an interslice spacing of 0.1439 mm.
Anderson, S., and J. K. Jones Jr. 1984. Orders and Families of Recent Mammals of the World. John Wiley and Sons, Inc., New York, NY. pp 686.
Desmond, M.J. 2004. Habitat associations and co-occurrence of Chihuahuan Desert hares (Lepus californicus and L. callotis). American Midland Naturalist 151: 414-419.
Hutchins M., D. G. Kleiman, V. Geist, and M. C. McDade. 2003. Grzimeck's Animal Life Encyclopedia, Second edition. Volumes 12-16 Mammals I-V. Gale Group, Farmington Hills, MI. pp 670.
Nowak, R. M. 1991. Walker's Mammals of the World, Volume 1. Johns Hopkins Univeristy Press, Baltimore, MD. pp 642.
Portales, G. L., L. Hernández, F. A. Cervantes, and J. W. Laundré. 2004. Reproduction of black-tailed jackrabbits (Lagomorpha: Lepus californicus) in relation to enviornmental factors in the Chihuahuan Desert, Mexico. The Southwestern Naturalist 49(3): 359-366.
Information and images of Lepus californicus on Animal Diversity Web (University of Michigan Museum of Zoology).
Information on the black-tailed jackrabbit on The Mammals of Texas Online.