OBSERVATIONS ON THE REACTIONS OF SEA LIONS, ZALOPHUS CALIFORNIANUS AND EUMETOPIAS JUBATUS, TO KILLER WHALES, ORCINUS ORCA; EVIDENCE OF "PREY" HAVING A "SEARCH IMAGE" FOR PREDATORS


Robin W. Baird and Pam J. Stacey

Canadian Field-Naturalist 103:426-428. 1989.

Observations on the reactions of California sea lions (Zalophus californianus) and Steller sea lions (Eumetopias jubatus) to the presence of foraging transient killer whales (Orcinus orca) were made on three occasions. Alert and avoidance responses by sea lions were made in the presence of killer whales of typical appearence. In the presence of a single, foraging killer whale of atypical appearance, no alert or avoidance response was observed. It is possible that the sea lions did not recognize the atypical whale as a killer whale, suggesting that sea lions may have a perceptual "search image" for the detection of predators, based on visual cues.

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