Hispid Cotton Rat 
59 
Haines, H. 1961. Seasonal changes in the reproductive organs of the cotton 
rat, Sigmodon hispidus. Texas J. Sci. 8:219-230. 
Hall, E. R. 1981. The Mammals of North America. John Wiley and Sons, New 
York. 
Jameson, E. W., Jr. 1950. Determining fecundity in male small mammals. J. 
Mammal. 31:433-436. 
Keller, B. L., and C. J. Krebs. 1970. Microtus population biology: III. 
Reproductive changes in fluctuating populations of M. ochrogaster and M. 
pennsylvanicus in southern Indiana, 1965-1967. Ecol. Monogr. 40:263-294. 
Kilgore, D. L., Jr. 1970. The effects of northward dispersal on growth rate of 
young, size of young at birth, and litter size in Sigmodon hispidus. Am. 
Midi. Nat. 84:510-520. 
Lewis, J. B. 1944. Cotton rat in lower piedmont Virginia. J. Mammal. 
25:195-196. 
McClenaghan, L. R., Jr. 1977. Genic variability, morphological variation and 
reproduction in central and marginal populations of Sigmodon hispidus. 
Ph.D. dissertation, Univ. Kansas, Lawrence. 
McClenaghan, L. R., Jr., and M. S. Gaines. 1978. Reproduction in marginal 
populations of the hispid cotton rat {Sigmodon hispidus) in northeastern 
Kansas. Occas. Pap., Univ. Kan. Mus. Nat. Hist. 74:1-16. 
Meyer, B. J., and R. K. Meyer. 1944. Growth and reproduction of the cotton 
rat, Sigmodon hispidus hispidus, under laboratory conditions. J. Mammal. 
25:107-129. 
Pagels, J. F. 1977. Distribution and habitat of cotton rat {Sigmodon hispidus ) 
in central Virginia. Va. J. Sci. 28:133-135. 
Patton, C. P. 1941. The eastern cotton rat in Virginia. J. Mammal. 22:91. 
Randolph, P. A., J. C. Randolph, K. Mattingly, and M. M. Foster. 1977. 
Energy costs of reproduction in the cotton rat, Sigmodon hispidus. Ecology 
58:31-45. 
Sadleir, R. M. F. S. 1969. The ecology of reproduction in wild and domestic 
mammals. Methuen and Co., Ltd. 
Sauer, J. R. 1985. Mortality associated with severe weather in a northern 
population of cotton rats. Am. Midi. Nat. 113:188-189. 
Slade, N. A., J. R. Sauer, and G. E. Glass. 1984. Seasonal variation in field- 
determined growth rates of the hispid cotton rat {Sigmodon hispidus ). J. 
Mammal. 65:263-270. 
Smith, M. H., and J. T. McGinnis. 1968. Relationships of latitude, altitude, 
and body size to litter size and mean annual production of offspring in 
Peromyscus . Res. Pop. Ecol. (Japan) 10:115-126. 
Zimmerman, E. G. 1970. Karyology, systematics and chromosomal evolution 
in the rodent genus, Sigmodon. Mich. State Univ., Mus. Publ., Biol. Ser. 
4(9):385-454. 
Accepted 14 April 1989 
