SPERM WHALES! Sperm whales are the largest toothed whale. The Sperm whale has the biggest head of any animal; it can be up to 20 feet long (6m), and is about one-third of the whale's body. Its lower jaw is small and contains its huge, conical teeth. Sperm whales are carnivores (meat-eaters) that mostly hunt giant squid that live on the ocean bottom at great depths. They also eat fish, octupus, and skate.