Meeting Abstract
P3.14 Sunday, Jan. 6 Don\\\\\\\\\\\\\\\’t Bite Your Mother: Seasonality and Sex Differences in Dolphin Tooth Rake Marks NEKOLNY, S.*; GIBSON, Q.; ERMAK, J.; RICHMOND, J.; University of North Florida; University of North Florida; University of North Florida; University of North Florida s.nekolny@unf.edu
Although aggressive encounters among conspecific dolphins are rarely observed, tooth rake marks that result from such interactions serve as a useful tool for evaluating aggression levels in a population. This study examined seasonality and sex differences in recency and body coverage of tooth rake marks on bottlenose dolphins (Tursiops truncatus) in Jacksonville, Florida (n=278 dolphins). Photographs (n=2395) from March 2011 through February 2012 were examined for dorsal surface rake marks. The dolphin body was divided into seven sections and each section was assigned a code for the percentage of rake mark coverage (> or < 50%). Rake marks were categorized as new, obvious, or faint. The female sex category included individuals with confirmed calves, while unknown sex included behaviorally presumed males and a few possible females not yet observed with a calf. The percentage of dolphins with rake marks was high in all seasons (range=92.6—99.2%). Both females (96.9%) and unknown sex (100%) were most likely to have rake marks in winter, but spring also had a high percentage of females with rakes (95.8%). In all seasons except spring, fewer females than unknown sex had rake marks. Winter had the greatest incidence of new rakes for both females (22.6%) and unknown sex (50.5%). Winter also had the highest percentage of both females (61.3%) and unknown sex (65.6%) with extensive coverage of rakes in at least one body section. Individuals with rakes present on at least four body sections were most abundant in spring for females (16.7%) and winter for unknown sex (24.7%). These results indicate that conspecific aggression occurs more frequently in winter and among individuals of unknown sex than females.
