A study of the prenatal and postnatal growth and development of beaver (Castor Canadensis Kuhl)

The prenatal and postnatal body development of beavers in Southwestern Nova Scotia was examined using measurements from over 300-dead-trapped and over 25 live-trapped beaver taken from the Tobeatic Wildlife Management Area as well as 59 litters from pregnant females trapped province wide. Conception and parturition dates were estimated, and all fetuses and embryos aged by two separate methods, using criteria of morphological development as well as a linear regression of logₑ weight vs. logₑ hind foot length. Early postnatal weights and measurements were analyzed, and seasonal changes in development well documented. Beavers from areas differing in soil productivity and quality of beaver habitat were compared with respect to their weights and measurements of various comparative ages. Weight increments of kit beavers from the area of higher productivity were found to be significantly higher, but these increments were comparable in beavers from both areas in all other age classes considered. Male and female beavers were also compared and found to be very similar with respect to differences in weights and measurements in each age class.