Meeting Abstract
9.5 Jan. 4 Ontogeny of Feeding Performance and Skull Morphology in the Spotted Hyena TANNER, J. B.*; ZELDITCH, M. L.; LUNDRIGAN, B. L.; HOLEKAMP, K. E.; Michigan State University, East Lansing; University of Michigan, Ann Arbor; Michigan State University, East Lansing; Michigan State University, East Lansing tannerja@msu.edu
Ontogeny in the spotted hyena Crocuta crocuta is characterized by dramatic behavioral and morphological change. These large, social carnivores feed in intensely competitive environments in which the ability to quickly consume large quantities of food is highly advantageous. Spotted hyenas are also capable of cracking open and consuming large bones. Consequently, their skulls are highly specialized for durophagy, with enormous sagittal crests and wide zygomatic arches providing increased attachment area for muscles critical in bite force generation. In this study we used geometric morphometric techniques to quantify ontogenetic changes in skull size and shape. We analyzed the ventral and lateral views of 65 Crocuta skulls ranging in age from 1 day to 17 years. Additionally we conducted feeding performance tests using standardized objects such as dog biscuits and goat femurs to measure age-related changes in feeding speed. Lastly, we calculated bite force estimates from measurements of the skulls and performed partial least-squares analyses to investigate the relationship between specific changes in the skull and bite force. We find that Crocuta skulls continue to grow and change shape past 30 months of age although this is long after the average weaning age of 14 months. Likewise, feeding speed and bite force continue to increase significantly until 35 months of age. We thus conclude that the development of the feeding apparatus is significantly delayed although selection should favor rapid improvement in feeding performance in such competitive feeding environments. This delayed development in the feeding apparatus ultimately may provide insight into the adaptive significance of the unusual trait of female dominance in this species.
