The sperm whale (Physeter catodon), also known as the cachalot, is the largest toothed whale. It has the biggest head of any animal. The head can be about long, and is about one-third of the whale's body. It also has biggest brain in the entire animal kingdom. Its lower jaw is small and contains its huge, conical teeth. These teeth fit into sockets in the upper jaw.
Diet
Sperm whales are carnivores (meat-eaters). They mostly hunt medium-sized squid. They also eat many kinds of fish such as skate. Sometimes they hunt giant squid that live on the ocean bottom at great depths. They can dive up to 2250 m and stay underwater for two hours.
Size
Sperm whales can reach up to 20.7m long, and weigh up to 80,000kg. There is disagreement on the claims of adult males approaching, reaching or exceeding 24m in length.
Echolocation
Like other toothed whales, the sperm whale uses echolocation, a way of sensing in which they emit high-pitched clicks and sense them as they bounce back off objects (like prey). This is crucial in hunting in the dark ocean depths.