Killer whales, despite their name, are the largest members of the dolphin family. They are well known for their unique black and white coloration and for being one of world’s top predators.
- U.S. Endangered Species Act (ESA) – Endangered, southern residents
- U.S. Marine Mammal Protection Act (MMPA) – Depleted, AT1 transients & southern residents
- International Union for the Conservation of Nature (IUCN) – Data Deficient
Adult male killer whales average 9.8 m (32 feet) and 10,000 kg (10 tons) while the smaller females average 8.5 m (28 feet) and weigh 7,500 kg (7.5 tons). They have a black body with a distinctive white chest and sides and white patches above and behind the eyes. Just behind the dorsal fin is a dark gray “saddle patch”. Each individual whale has a uniquely shaped and scarred dorsal fin as well as a unique saddle and eye patch which researchers use to identify them. Flippers are paddle shaped, broad, and round. Their flukes are notched and slightly concave and can reach 2.7 m (9 feet) in breadth. They have conical teeth that are curving, interlocking and pointed slightly inward and backward that help them grasp and tear prey.
Distribution and migration
Killer whales range worldwide, and individuals belong to regional ecological groups, called ecotypes. There are three major ecotypes found within the California Current: residents, transients, and offshore killer whales. The easiest to encounter is the southern resident killer whale ecotype. They reside in the inland seas of Washington and British Columbia and consist of a group of 71 to 96 individuals. The northern resident group, with a maximum of 216 individuals, ranges from British Columbia to Alaska. The transients range from southern California to Alaska, and minimum estimates for the group is about 314 individuals. With such a vast range, they are rarely seen. The offshore ecotype is likely made up of more than 450 individuals.
Killer whales favor colder, fertile waters near coasts, but the offshore ecotype ranges to destinations that are unknown. Most sightings are within 800 km (500 miles) from shore.
Feeding style and diet
The diet of killer whales can vary by region and animals can take a variety of prey, including many species of marine mammals, from fast-swimming Common Minke whales to sea otters. The resident whales of Washington and British Columbia will often prey on harbor seals. In Monterey Bay, California, gray whale calves on their northbound migration with their mothers are targeted. In central California, large whales, like the Humpback whale, may also become prey. Other ecotypes will feed on bony fishes, sharks, rays, squid and octopuses. In the Pacific northwest, killer whales almost exclusively feed on salmon, while in the Antarctic, whales may occasionally take penguins. Killer whales will often hunt in cooperation with each other, employing special, learned techniques that often vary by ecotype or region.
Other common species found on the west coast
Want to learn more about whales along the west coast?
Check out the Field Guide to MARINE MAMMALS of the Pacific Coast, a California Natural History Guide by Sarah G. Allen, Joe Mortenson, and Sophie Webb.