(Linnaeus, 1758) - Killer whale
Killer whales are among the most distinctive, and therefore easily identified, of all cetaceans. The tall erect dorsal fin is nearly as distinctive as the colour pattern. It may reach 0.9 m in females and 1.8 m in males. Adult males tend to have dorsal fins that are triangular or that may even cant forward to varying degrees. Killer whales have blunt snouts, with only very short and poorly defined beaks. The flippers are large and oval, and grow to lengths of up to 2 m in bulls.
The black-and-white colour pattern is unmistakable. The lower jaw, undersides of the flukes, and ventral surface from the tip of the lower jaw to the urogenital area is white. White lobes extend up the sides behind the dorsal fin, and there is a white oval patch above and behind each eye. The rest of the body is black, except for a light-grey “saddle patch” behind the dorsal fin. In some populations, the dorsal coloration includes a narrow black cape, below which the dark areas are more nearly charcoal grey.
There are 10 to 12 large, recurved teeth in each half of both jaws, which are oval in cross-section. In older animals, they are often worn and damaged by abscesses.
Can be confused with
Killer whales are easily recognizable to almost anyone who has spent time on the water or along the coast in areas they frequent. The great size of the dorsal fin (especially of adult males) and unique black and white colour pattern are diagnostic. At a distance, groups without adult males can be confused with Risso's dolphins and false killer whales.
Newborn killer whales are 2.1 to 2.4 m in length and about 180 kg in weight. Adult females are up to 8.5m and 7500 kg; adult males up to 9.8 m and nearly 10000 kg.
This is probably the most cosmopolitan of all cetaceans. They can be seen in literally any marine region, and killer whales have even been known to ascend rivers. Killer whales are found in all oceans and seas, from the ice edges to the equator, in both hemispheres; however, they appear to be more common in nearshore, cold temperate to subpolar waters.
Biology and Behaviour
Studies in the eastern North Pacific, from Washington State to Alaska, have distinguished 2 types of killer whales, referred to as residents and transients. Although differentiated by ecological differences, there are also differences in coloration and external morphology. In Washington and British Columbia, at least, residents are primarily fish eaters and transients eat mostly marine mammals. Some studies in other parts of the world suggest that this pattern may be universal. Pods of resident killer whales in British Columbia and Washington represent one of the most stable societies known among non-human mammals; individuals stay in their natal pod throughout life. Differences in dialects among sympatric groups appear to help maintain pod discreteness. Most pods contain 1 up to 55 whales and resident pods tend to be larger than those of transients.
In the Pacific Northwest, calving occurs in non-summer months, from October to March. Similarly, in the northeast Atlantic, it occurs from late autumn to mid-winter.
Though best known for their habits of preying on warm-blooded animals (killer whales are known to have attacked marine mammals of all groups, from sea otters to blue whales, except river dolphins and manatees), killer whales often eat various species of fish and cephalopods. Killer whales also occasionally eat seabirds and marine turtles.
Pelagic whaling activities have rarely directed their attention towards killer whales, but whaling fleets have taken a few in most years. Very small numbers of killer whales were taken in the North Pacific by now-defunct shore whaling stations. Fishermen in many areas see killer whales as competitors, and shooting of whales is known to occur. This problem is especially serious in Alaska, where conflicts with longline fisheries occur. Small numbers are taken incidentally in fisheries in many areas.Live captures for public display have been banned in most areas of the eastern North Pacific. Subsequently, live capture activities shifted to Iceland, but in 1991, the Icelandic government announced that once current permits for live capture expire, no new ones will be issued.