Diet & Eating Habits

Killer Whales

Diet & Eating Habits

Food Preferences & Resources

  1. Killer whales are active predators that eat a wide variety of fishes, squids, and marine mammals. 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 alive today.
    • Killer whales eat a wide variety of fishes, from surface-swimming salmon to bottom-dwelling halibut. They frequently prey on cod, hake, herring, and smelt.
    • Some killer whales eat marine mammals including seals, sea lions, baleen whales, other toothed whales, walruses, and occasionally sea otters.
    • Polar bears, reptiles, and even a moose have been found in the stomach contents of killer whales.
    • 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. Perhaps they scavenged the remains of dead killer whales, as killer whales are known to eat the remains of other animals.
    • Some killer whales eat penguins and seabirds.
    • Observations in New Zealand suggest that some killer whales there specialize in hunting elasmobranchs such as thresher sharks (Alopias vulpinus), smooth-hammerhead sharks (Sphyrna zygaena), manta rays (Manta birostris) and several others.
  2. The diets of killer whales vary from one region to another.
    • The three forms of Antarctic killer whales differ in their diet. "Type A" whales eat mostly Antarctic minke whales. "Type B" whales eat mainly seals, but also prey on minke and humpback whales. "Type C" killer whales eat mostly Antarctic toothfish (Dissostichus mawsoni).
    • The feeding habits of resident and transient whales of the eastern North Pacific Ocean differ.
      • Resident whales spend about 60% to 65% of daylight hours foraging. They eat a variety of fish and only rarely eat marine mammals. Salmon is a main food source for these whales.
      • Transient whales spend about 90% of daylight hours foraging. They eat primarily marine mammals and only occasionally eat fish. They prey on seals, sea lions, walruses, baleen whales, other toothed whales, and occasionally sea otters.
      • Researchers theorize that the divergent, specialized feeding habits of resident and transient killer whales help prevent these two groups of whales from competing with each other for food. Furthermore, these different feeding habits have resulted in significant differences in vocalizations, echolocation, group size, and behavior between the two groups.

Food Intake

  1. At SeaWorld parks, adult killer whales eat approximately 2% to 4% of their body weight in food per day.
  2. Growing calves eat more - as much as 10% of body weight during growth periods.
    • At zoological parks, calves begin to take a few fish at about two to three months.
    • A killer whale’s lower teeth emerge at about four months.
    • By the age of one year, calves at SeaWorld eat 23 to 27 kg (50–60 lb.) of herring, smelt, and squid per day.
  3. Killer whales don’t chew their food. They swallow their food whole, or they may tear or shred it.
  4. Killer whales swallow their food in chunks if need be, but their throats are large enough to swallow small seals and walruses whole.

Methods of Collecting Food

  1. Killer whales often hunt cooperatively in pods for food.
    • At times killer whales work together to encircle and herd small prey before attacking. The comparatively large pod size of resident whales is an advantage when herding a school of fish.
    • Researchers observed Norwegian killer whales hunting cooperatively using a "carousel-feeding" technique. They cooperatively herded small fishes into a tight ball close to the surface. Then the whales stunned the fishes with their tail flukes and ate the stunned fish.
    • To hunt a large baleen whale, a pod of killer whales may attack the whale from several angles. One attack was witnessed by SeaWorld researchers. About 30 killer whales attacked an 18.2-m (60-ft.) blue whale. Two killer whales stayed ahead and two brought up the rear while the others surrounded the blue whale from the sides and underneath in an apparent effort to prevent escape. Some leaped onto its back. The whales took turns biting flesh and blubber from their prey. After five hours the pod broke off the attack.
    • A New Zealand researcher described a group of seven killer whales hunting a shortfin mako shark (Isurus oxyrhinchus). The whales thrust their tail flukes underwater to force the shark toward the surface, then struck the shark with their tail flukes before killing and eating it.
    • Transient pods "sneak-attack" marine mammals. These small groups most often hunt quietly or silently.
  2. Killer whales also hunt individually.
    • In the Antarctic, killer whales slide out onto ice floes to hunt penguins. Similarly, killer whales sometimes slide up onto sand bars or beaches to hunt sea lions.
    • Killer whales sometimes hit ice floes from below to knock prey into the water.
    • An encounter between a great white shark (Carcharodon carcharias) and killer whales were 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.
      • Perhaps the smell of fresh sea lion blood drew the shark to the area, but once one of the killer whales sighted the great white it immediately charged the shark and contacted it under water. The killer whale pulled the 3 to 4 m (10-13 ft.) shark to the surface in its mouth and the killer whales consumed sections of the great white such as its enormous liver.
      • This is certainly no indication of what may happen every time killer whales face great whites, but it does demonstrate the variety of a killer whale's diet.
      • Prey such as these sea lions, may not
        be safe from killer whales even on land.

  3. Sometimes killer whales feed in connection with fisheries operations, eating fishes that slip from the nets and bycatch (nontarget fish caught during a fishing operation) discarded by fishermen. In some areas, killer whales congregate near longline boats and feed on the hooked fish.
  4. Killer whales possess sharp, cone-shaped
    teeth adapted for ripping and tearing prey.