Comparative Reproduction and Development in Two Species of Mice in the Genus Peromyscus

Abstract

The white-footed mouse, Peromyscus leucopus noveboracensis, and the deer mouse, Peromyscus maniculatus bairdii, are closely related species of the rodent family Cricetidae. The two resemble each other in many ways, but there are several characters by which they can be readily distinguished (Table 1). P. 1. noveboracensis is the larger of the two species and inhabits primarily woodlands or brushy areas. The dorsal coloration generally is a cinnamon brown, somewhat darker middorsally. The venter is white as in P. m. bairdii. The tail is bicolored (but not strikingly so except in a few individuals in winter pelage), the upper one-third being brownish and the lower two-thirds white. The braincase of P. 1. noveboracensis is