The sperm whale is the marine mammal known for deep-water echolocation and a bulbous forehead.
Its forehead contains the spermaceti organ, a large structure filled with a waxy substance. The organ is associated with the production and focusing of powerful clicks used for echolocation. Sperm whales can locate prey in darkness at depths where sunlight does not reach.
They are the largest toothed whales. Their diet includes squid and fish, and individuals can make exceptionally deep dives lasting well over an hour. The famous giant squid is a natural prey item, although encounters are difficult to observe directly.
The species was heavily hunted for centuries because spermaceti and other products were commercially valuable. The name comes from the historical mistaken belief that the spermaceti organ contained whale semen. Modern populations still face risks from ship strikes, entanglement, underwater noise, and pollution.