P1.93 Wednesday, Jan. 4 RESPIRATORY AND OLFACTORY TURBINATE SIZE IN CANID AND ARCTOID CARNIVORANS GREEN, P.*; PANG, B.; VAN VALKENBURGH, B.; University of California, Los Angeles; University of Massachusetts, Amherst; University of California, Los Angeles; University of California, Los Angeles email@example.com
It is widely assumed that dogs (Family Canidae) have an exceptional sense of smell, however there is little comparative evidence to support this claim. We used 3D visualization of CT scans to measure the bony surface areas of olfactory (OSA), respiratory (RSA) and, combining these, total (TSA) turbinates in skulls of 10 species of canids as well as 12 previously studied, terrestrial species of the Superfamily Arctoidea (Ursidae, Mustelidae, Mephitidae, Procyonidae). We examined scaling relationships and asked if ecological variables such as diet and home range size correlate with olfactory ability, as shown by ratios of OSA and RSA. After phylogenetic correction, we found that canids show greater positive allometry in TSA relative to arctoids, as a result of positive allometry in OSA and isometry in RSA. Canids also have a greater proportion of their turbinate area devoted to olfaction than respiration, suggesting that canids have enhanced olfactory ability relative to most arctoids. Interestingly, two arctoid species, the wolverine (Gulo gulo) and polar bear (Ursus maritimus) are similar to canids in having enlarged olfactory turbinates. An expanded olfactory region in both these species and the larger canids is associated with hypercarnivory as opposed to omnivory. We suggest that this reflects selection for greater olfactory ability in large, meat-eating species in response to their dependence on widely dispersed, relatively sparse resources (large vertebrate prey). Future research will use histology and flow visualization to more deeply investigate nasal chamber structure and function in mammals.