The hispid cotton rat, Sigmodon hispidus Say and Ord, a species of the southwestern United States that has been moving northward and eastward in this century, was first observed in Virginia in 1940. In this study of the cotton rat in southeastern Virginia, most males were reproductively competent from February through November, embryos were recorded from March through October, and litter sizes were comparable to those from other locations except Kansas. Also unlike the cotton rat in Kansas, animals grew at substantial rates during the winter in Virginia. The hispid cotton rat seems to have adjusted its breeding season in Virginia by the cessation of breeding early in autumn, which permits the last young of the season to attain nearly adult size before winter arrives. Both young and adults are able to maintain and even increase their autumnal body mass throughout the winter. Timing and length of the breeding season and the patterns of body growth suggest that the hispid cotton rat is well adapted to winter, and hence to persistence of the species, in southeastern Virginia.
Original Publication Citation
Rose, R. K., & Mitchell, M. H. (1990). Reproduction in the hispid cotton rat, Sigmodon-hispidus say and ord (Rodentia: Muridae), in southeastern Virginia. Brimleyana, 16(1), 43-59.
Rose, Robert K. and Mitchell, Michael H., "Reproduction in the Hispid Cotton Rat, Sigmodon-hispidus Say and Ord (Rodentia: Muridae), in Southeastern Virginia" (1990). Biological Sciences Faculty Publications. 427.