THE WORLD’S LARGEST DOLPHIN
When Is A Whale Not A Whale?
Really? The Killer Dolphin?
Orcas certainly look like whales to us. After all, they grow to a length of 30 feet. But scientists have classified them as being in the same family—Delphinidae—as the 31 other species of ocean-dwelling dolphins, most of which are so much smaller than orcas that orcas would gladly eat them if they had a chance.
Although the orca’s huge size seems un-dolphinlike to us, its curved dorsal fin and pyramid-shaped teeth identify it as a true member of the dolphin family. Orcas also travel in large family groups, which is a behavioral characteristic that distinguishes dolphins from other, less gregarious, kinds of cetaceans such as propoises and baleen whales.
Nonetheless, it is not incorrect to refer to any member of the dolphin family, including the orca, as a whale. All dolphins belong to the Cetacean sub-order of toothed-whales—a group that also includes porpoises and sperm whales.
One especially fascinating thing about killer whales is that they are such intelligent and cooperative hunters, as this video shows.
Feature for kids: If you want to learn more about how orcas and whales fit into their food web, visit our sister website, What Eats?, to read what eats a walrus? and what eats a whale?
