VIOLENT INTERACTIONS BETWEEN BOTTLE-NOSED DOLPHINS AND HARBOR PORPOISES

The majority (63%) of harbour porpoises stranded around the Moray Firt h, Scotland, died from trauma characterized by multiple skeletal fract ures and damaged internal organs. Surface injuries consisted of skin c uts resembling the teeth marks inflicted by one cetacean on another. T he spacings between these matched those between teeth in bottlenose do lphins, of which there is a population in the Moray Firth. Four violen t dolphin-porpoise interactions have been witnessed. Reasons for these interactions are unknown and similar documented examples between othe r mammals are extremely rare. These findings challenge the benign imag e of bottlenose dolphins and provide a hitherto unrecorded cause of mo rtality in porpoises.