Abstract

The killer whale (Orcinus orca) distributed in the Eastern Tropical Pacific may represent a new ecotype with distinct morphological and ecological characteristics, among them, a generalist feeding habit that includes marine mammals, sea turtles, elasmobranchs, and bony fishes. Some of these prey species have been previously reported for the Mexican Central Pacific; however, three additional prey species have been recorded in recent years. A whale shark (Rhincodon typus), a spinner dolphin (Stenella longirostris), and black sea turtle (Chelonia mydas agassizii) were preyed by killer whale individuals presenting the morphological characteristics of the Eastern Tropical Pacific ecotype; some of them had been previously reported as potential prey. This represents an expansion of the killer whale prey list and shows that a very generalist feeding habit is one of the main characteristics of this killer whale ecotype, which has displayed surprising hunting tactics that need to be investigated further to obtain sufficient information to ensure its conservation.

Keywords:Killer whales; Ecotype; Eastern tropical pacific; Prey items

Abbreviations: KW: Killer Whale; ENP: Eastern North Pacific; ETP: Eastern Tropical Pacific; MCP: Mexican Central Pacific