Inside a Sperm Whale's Mouth

Preview Photo taken of the inside of a sperm whale's mouth. The teeth on the lower jaw fit into sockets above- perfect for eating squid.
(©Clyde F.E. Roper)

Sperm whales have conical teeth on their long, narrow, lower jaw. The teeth fit neatly into sockets in the upper jaw, which has no teeth. This arrangement is a perfect adaptation for slurping up soft-bodied squids—giant or otherwise. The sperm whale is listed as Vulnerable on the IUCN's Red List of Threatened Species.