Diet and Eating Habits
A. Food preferences and resources.
1. Active and opportunistic, killer whales are without a doubt top predators in the ocean. In fact, they are the largest predator of warm-blooded animals ever known.
2. Fishes, squids, seals, sea lions, walruses, birds, sea turtles, otters, penguins, cetaceans (both mysticete and odontocete), polar bears, reptiles, and even a moose -- they have all been found in the stomach contents of killer whales.
3. Perhaps the most interesting thing found in the stomachs of killer whales is the remains of other killer whales. How this came to be is uncertain as killer whale predation on other killer whales is rare. Perhaps they scavenged the remains of dead killer whales, as killer whales are known to eat the remains of other animals.
4. The diets of killer whales vary from one region to another.
B. Food intake.
C. Methods of collecting food.
1. Much like packs of wolves or prides of lions, killer whales often hunt cooperatively in pods for food. They work together to encircle and herd prey into a small area before attacking. When hunting a large whale, a pod of killer whales may attack from several angles.
2. The conical and interlocking teeth of killer whales are adapted for ripping and tearing but not for chewing. The number of teeth varies among individuals. There are usually 10 to 14 teeth on each side of the jaw -- a total of 40 to 56 teeth. Each tooth is about 7.6 cm (3 in.) long and approximately 2.5 cm (1 in.) in diameter.
3. Killer whales swallow their food in chunks if need be, but their throats are large enough to swallow small seals and walruses whole.
4. Prey, such as these sea lions, may not be safe from killer whales even on land. Some killer whales specialize in sliding out onto sand bars or ice floes to pursue prey. They may also hit ice floes from below to knock prey into the water.
5. Another rare event, an encounter between a great white shark (Carcharodon carcharias) and killer whales, was recently documented off of Southeast Farallon Island near San Francisco, California. Two killer whales were in the area feeding on a California sea lion (Zalophus californianus) -- a favored food of great whites.
6. A pod of 30 to 40 killer whales was seen following a fleet of trawler ships in the northeastern area of the Shetland Islands in the United Kingdom. As the trawlers brought aboard quantities of netted mackerel (Scomber scombrus), the killer whales consumed fishes that slipped from the nets or dead fishes tossed off the ships.
7. Research has shown that resident whales have a wider sound repertoire than transient whales, which may be partially related to their hunting habits.
Killer whales have a complex relationship with other marine mammals. Killer whales have been observed feeding on fish while in the company of other dolphins, minke whales (Balaenoptera acutorostrata), and Dall's porpoises (Phocoenoides dalli). On another occasion, humpback whales (Megaptera novaeangliae) joined a pod of killer whales that were attacking a Stellar sea lion (Eumetopias jubatus). At other times seals have been seen swimming with killer whales. All of these animals may all be prey of killer whales at other times.
©2002 Busch Entertainment Corporation.