Attacks on sea otters by killer whales

Few references to attacks on sea otters, Enhydra lutris, by killer whales, Orcinus orca, exist in the literature. In an extensive review of predatory and non-predatory interactions between killer whales and other marine mammals, Jefferson et al. (1991) cited only one reference (Nikolaev 1965) in which killer whales aggressively pursued sea otters. In another review of attacks on marine mammals by killer whales in the North Pacific Ocean, Matkin and Saulitis (1994) listed three other interactions between killer whales and sea otters, but with the exception of one personal communication, the references (Barabash-Nikiforov 1938, Tomilin 1957) alluded only to presumed attacks. Kenyon(1969) described only non-aggressive interactions between the two species. No descriptions of killer whale attacks on sea otters have been published. In this note we describe nine observations made between 1992 and 1996 of killer whales attacking sea otters in Prince William Sound and in the Aleutian Islands, Alaska.