Meeting Abstract

P3.45  Thursday, Jan. 6  Craniodental Morphology and Bite Performance in Otters (Lutrinae) TIMM, Lori*; MARSHALL, Christopher D; Texas A&M University, Galveston and College Station; Texas A&M University, Galveston and College Station lori_timm@yahoo.com

Otters (Mustelidae: Lutrinae) display a diversity of feeding adaptations that likely correspond to craniodental morphology and bite performance. Craniodental morphology and bite performance have not been investigated in otters within a comparative and ecomorphological context. To begin to characterize feeding capabilities of otters, we measured relative estimated bite forces in two subspecies of sea otters (Enhydra lutris kenyoni, E. l. nereis) and North American river otters (Lontra canadensis) using a dry skull method, biomechanically relevant craniodental morphology, and maximum breaking force of bivalve prey of sea otters (Saxidomus giganteus and Protothaca staminea). We hypothesized that sea otters possessed a stronger bite force than river otters, and that the craniodental morphology of sea otters varied significantly between subspecies and from river otters. Bite force differed among otters measured. Enhydra l. nereis, which preys primarily on hard benthic prey, showed the greatest bite force. Mechanical advantage of the temporalis and masseter muscles were significantly different (p<0.001 and p=0.003, respectively) among all otters. Enhydra l. kenyoni and E. l. nereis. had a significantly lower temporalis mechanical advantage (0.008, each) than L. canadensis (0.009). Enhydra l. kenyoni and L. canadensis possessed greater masseter mechanical advantages (0.006, each) than E. l. nereis (0.005), suggesting a variety of mechanisms that produce high bite forces. Significant differences in mandibular bluntness (p<0.001) was also shown among all species. All sea otters possessed a greater MBI and greater skull widths (p=0.04) than L. canadensis, suggesting skull and mandibular width is mechanically related to bite force production.