Orca whales, also known as killer whales, can grow up to 33 feet long and weigh over 12,000 pounds. They live in oceans around the world, though prefer cold waters, and can be found off the coasts of places like Washington, Oregon and California. Orcas hunt in family pods of up to 40 individuals and cooperate to prey on other marine mammals like seals, sea lions and other whales, as well as fish. They communicate using echolocation and a variety of sounds. As top predators, orcas have no natural predators besides sharks and humans, though can suffer from diseases.