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

Abstract

Observations on the reactions of California Sea Lions (Zalophus californians) and Steller Sea Lions (Eumetopias jubatus) to the presence of foraging transient Killer Whales (Orcinus orca) were made on three occasions. Alert and avoidence responses by sea lions were made in the presence of Killer Whales of typical appearance. 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.