128731 Scrimshaw - Sperm whale tooth. Sperm Whale Physeter macrocephalus Length 16-20m Huge, distinctive whale with large, bulbous head. Tail is raised clear of water prior to deep dive. Dives to 2,000m or more in search of giant squid and sharks. Females live in social groups. Adult is blackish grey with whitish scars from fights and violent encounters with prey. Head accounts for roughly 1/3 of body length and mass. Lower jaw is slender and armed with sharp teeth. Dorsal fin is absent but note dorsal ‘hump’ and series of knobbly lumps. Flippers are small while tail is large. Has a single blowhole (baleen whales have 2); sited at front of head and angled slightly forward and to left.