Because of its large size and formidable defenses, The Pacific electric ray seldom falls prey to other animals. There is a record of one being fed upon by a killer whale ("Orcinus orca") off Santa Catalina Island. The Cooper's nutmeg ("Cancellaria cooperi") is a specialized parasite of this ray, and possibly other bottom-dwelling fishes such as the Pacific angelshark ("Squatina californica"). The snail is attracted to the chemicals contained in the ray's surface mucus; it makes a small cut on the ventral surface of the ray and uses its proboscis to suck blood. Other known parasites of this species include the copepod "Trebius latifurcatus", the fluke "Amphibdelloides maccallumi", and the tapeworm "Acanthobothrium hispidum".