Intraspecific variation in life-history traits of the white-tailed jackrabbit (Lepus townsendii)

Publication Type:

Journal Article

Authors:

Rogowitz, Gordon L.; Wolfe, Michael L.

Source:

Journal of Mammalogy, American Society of Mammalogists, Volume 72, Issue 4, p.796-806 (1991)

Call Number:

A91ROG03IDUS

URL:

http://www.jstor.org/stable/1381846,

Keywords:

Lepus townsendii, White-tailed Jackrabbit

Abstract:

The population structure and pattern of individual growth of white-tailed jackrabbits (Lepus townsendii) were studied in Wyoming and compared with results for more easterly populations in North America. The density of white-tailed jackrabbits in Wyoming was ca. 7/km2 and relatively constant during 1985–1987. Sex ratios of adults and young of the year were near 1:1. Age distributions of each sex were similar, with younger animals predominant. Typical lifespans of wild white-tailed jackrabbits were estimated to be <1 year. Projected annual survival rates (sexes combined) were 0.093 in 1985 and 0.20 in 1986. Sexual dimorphism, with slightly heavier females, was detected in nonreproductive white-tailed jackrabbits. Appendage lengths were also slightly dimorphic. White-tailed jackrabbits exhibited sigmoid growth; >90% of the variance in age-specific body masses was explained by fitting von Bertalanffy, Gompertz, logistic, or Richards sigmoid equations to data. Postnatal growth rates of white-tailed jackrabbits were 18–30 g/day during the linear phase of growth (20–80 days). A comparison of these results with those for other regions indicated little geographic variation occurs among populations of L. townsendii.