Killer Whales are well‐known as predators of other marine mammals, including the large Sperm and baleen whales. Members of all marine mammal families, except the river dolphins and manatees, have been recorded as prey of Killer Whales; attacks have been observed on 20 species of cetaceans, 14 species of pinnipeds, the Sea Otter, and the Dugong. Ecological interactions have not been systematically studied and further work may indicate that the Killer Whale is a more important predator for some populations than previously believed. Not all behavioural interactions between Killer Whales and other marine mammal species result in predation, however. Some involve ‘harassment’ by the Killer Whales, feeding by both species in the same area, porpoises playing around Killer Whales, both species apparently ‘ignoring’ each other, and even apparently unprovoked attacks on Killer Whales by sea lions. These non‐predatory interactions are relatively common. We conclude that interactions between Killer Whales and marine mammals are complex, involving many different factors that we are just beginning to understand.

Patterns of pigmentation of the post dorsal fin patch, or saddle patch, were analyzed from photographs of 372 resident and 99 transient killer whales (Orcinus orca) from British Columbia, Alaska, and Washington State. Of the five types of saddle patch analyzed, all were observed on residents, but only two occurred on transients. Differences in saddle patch shapes were independent of age and sex. Saddle patch pigmentation patterns were similar among clans within a community. Pigmentation patterns differed significantly between the resident and transient forms, between northern and southern residents, between northern and Alaskan residents, and between southern and Alaskan residents. As the saddle patch shape may be heritable to a large degree, these differences suggest genetic isolation of the populations. If so, this technique may be used to delineate stocks of killer whales from other areas.

No abstract

No abstract

No abstract