The evolution of skilled forelimb movements in carnivorans (original) (raw)

Emancipating the forelimbs from locomotion for use in other activities, such as food manipulation, is a major evolutionary milestone. A variety of selective forces and evolutionary correlates may influence the evolution of various degrees of skill with which the forelimbs are used. Using the order Carnivora as a test group, I assessed the relative influence of six factors: relative brain size, neocortical volume, manus proportions, body size, phylogenetic relatedness, type of locomotion and diet I developed a rating system to describe the dexterity of individual species and compared the scores to the six factors using modem comparative methods. Only phylogeny and diet were significantly correlated with forelimb dexterity. More specifically, forelimb dexterity tends to be higher in caniform than in feliform carnivorans and decreases with increasing specialisation on vertebrate prey. I conclude that food handling and feeding niche breadth have a significant effect upon the evolution of skilled forelimb movements. iv ACKNOWLEDGEMENTS Firstly, I wish to thank Ian Whishaw and Sergio Pellis for offering me the opportunity to be their graduate student at such short notice and for their unwavering support throughout my thesis research. They both provided me the freedom, willingly or not, to 'do my own thing', but were always there when I needed some guidance. I would not have arrived here at all, however, without the inspiration of John Nelson who first introduced me to the behavioural analysis of reaching and grasping and provided me with the intellectual freedom to investigate behavioural phenomena on my own. This project could not have been completed without the assistance of the helpful staff at the following zoological institutions which I relied upon for my behavioural observations: Assiniboine Zoo (Winnipeg, MB), Calgary Zoo (Calgary, AB), Los Angeles County Zoo