Mandible of the giant panda (Ailuropoda melanoleuca) compared with other Chinese carnivores: functional adaptation

The aim of this study was to understand the mandible of the giant panda in morphometric terms to explore differences between the giant panda and other carnivores distributed in China, in terms of functional adaptation. Twelve mandibular variables were studied using bivariate (allometry) and multivariate (principal components analysis, PCA, and discriminant functional analysis, DFA) tools. When deviations were produced from allometric baselines consisting of all the species studied, the giant panda displayed a much more developed mandibular structure than the bear, leopard, and tiger. This may be related to its specific dietary preference for bamboo, which has very strong fibers. Results also indicate that the mandibular structure among carnivores mainly reflects the differences in their dietary preferences and functional adaptation. Three groups were found referring to dispersal profiles expressed by the first two axes of PCA and DFA: (1) the two panda species – the herbivorous carnivores; (2) the black bear – the omnivorous carnivore; and (3) the tiger and leopard – the hypercarnivores. Nevertheless, a significant separation between the two panda species was also found with the profiles displayed by the first and third axes of DFA. In addition to no close evolutionary relationship and phylogenetic development, a noticeable separation between the two panda species found in DFA analysis may be associated with their variation in consuming different parts of the bamboo plant: the giant panda feeds on stems and the red panda feeds on leaves.