The catch of the day!
Killer whales are carnivore marine mammals, so their diet is full of meat gotten by hunting several species in their habitat. Since there are several ecotypes of killer whales, their eating habits are closely linked to the geographical area where they are located and with their population. Thus, the orcas in a specific region can specialize in hunting and consumption of a particular prey.
Orcas feed on a wide variety of prey, from small schooling fish to large baleen whales. These cetaceans are powerful predators, which are not intimidated by large, or bulky animals, and are known to be able to attack even sharks.
In general, killer whales feed on a large variety of fish, cephalopods and marine mammals. The estimated number of species consumed worldwide by orcas is around 140. They usually prey on squids, octopus, seals, sea lions, sea otters, rays, dolphins, sharks, baleen whales and of course, bony fishes. Occasionally, turtles and seabirds, including penguins are added to their diet.
However, the feeding habits of the different populations of orcas are well known. Resident killer whales, inhabiting eastern North Pacific waters, feed primarily on salmon, particularly chinook salmon or king salmon (Oncorhynchus tshawytscha). By contrast, transient orcas in the same region prefer marine mammals such as harbor seals (Phoca vitulina), elephant seals (Mirounga Genre), porpoises (Phocoenidae family), sea lions (subfamily Otariinae), minke whales (Balaenoptera acutorostrata and Balaenoptera bonaerensis) and others.
Across the world, in Norwegian waters, they go after schools of fish and manifest preference for herring (Clupea Genre). New Zealand waters orcas prefer rays and sharks (Both Elasmobranchii Subclass) and those living in Antarctic feed on seals (Family Phocidae), minke whales and several species of fish such as the Antarctic toothfish (Dissostichus mawsoni).
Hunting Strategies
This apex predator exhibits several techniques for hunting. They are favored by their anatomy and strength, but also by their intelligence and social behavior.
The behavior and hunting strategies depend on the type of killer whale and the prey. For example, those orcas that target schools of herring during migration can hunt alone or in groups. If hunting in groups, they must execute coordinated movements and establish an effective communication to surround the school and then hit them with the tail fin. This stun or kill the prey so killer whales can feed on them.
If the victim is a marine mammal, the orcas have to hit them with the tail or throw them in the air. The procedure to catch large baleen whales, usually involves all the members of the herd, as baleen whales are not small or weak animals. Therefore, to avoid the larger individuals they look to attack the smaller species, weak adults or calves. Once the prey is selected, they chase it for a long time until it is exhausted and usually got isolated from the rest of its group, then they block its way to the surface to get oxygen. This technique is also applied when they chase dolphins.
Some strategies have especially caught the attention of scientists. For example, in shallow waters close to the coast, they approach the beach to catch seals, sea lions or sea elephants to the point of getting almost stranded, although this does not happen. This bold behavior is taught to the young.
Moreover, some orcas raise their head out of the water to spot prey resting over small ice floes. After locating a prey, a group approaches strong enough to create a wave of considerable size and strength to drag the prey into the water or at least to the edge of the floe. Additionally, Orcas move the floating ice to get the prey into the water. When the prey falls, the Orca in the place of the fall feeds on it.
Killer whales do not use their teeth to chew, they swallow small prey whole. However, they need to break the bodies of large animals to eat them.
