Head Shape and Size in Cannibal and Noncannibal Larvae of the Tiger Salamander from West Texas

small morphs did not differ in slope or Y-intercept, and data for these two groups were pooled for comparison with cannibals. Each cannibal allometric regression had a lower slope than the corresponding noncannibal regression, but these differences were not significant. In addition, the Y-intercepts of cannibal regressions exceeded the Y-intercept of the appropriate noncannibal regression. These findings suggest that head size does not increase at a faster rate relative to body size in cannibals, but that cannibals begin with a larger head early in ontogeny. CANNIBALISM often has been viewed as a laboratory artifact or an anomaly occurring in unusually dense and stressful situations, but cannibalism occurs in natural populations of a number of species and apparently is a common phenomenon in nature (Fox, 1975a). The circumstances under which cannibalism occurs