Cooperative Fish and Wildlife Research Units Program: Georgia
Education, Research and Technical Assistance for Managing Our Natural Resources

Maehr, D. S., and C. T. Moore. 1992. Models of mass growth for 3 North American cougar populations. Journal of Wildlife Management 56:700-707.


Previous studies of cougar (Felis concolor) physiology and population dynamics relied on growth curves of cougars obtained from diverse locations and under various rearing conditions. We were concerned about potential biases in studies that make but do not test the implicit assumption of homogeneity of growth characteristics among collection sites. Thus, we compared body masses of wild cougars from populations in Florida (F. c. coryi), Nevada (F. c. kaibabensis), and California (F. c. californica). We modeled mass as a nonlinear Richards function of age for each sex and population demographic group. Groups were consistent with respect to estimated birth mass and location of the inflection point of the growth curve. Adult mass was greater (P < 0.001) in males than females in all populations, and the size of the difference was similar among populations. Estimated adult masses of Florida and California cougars were not different (P = 0.381) from each other but were less (P < 0.001) than that of adult Nevada cougars. Growth rate varied by population but not by sex; Nevada cougars grew fastest to adult mass. Cougar mass is too variable to serve alone as an indicator of age beyond 24 months. Failure to control for population-specific influences on growth may bias inferences about growth.