Common Name: Sperm Whale
General Description: The Sperm Whale, the largest of the toothed whales, has a distinct and unusual shape. Its head is huge, making up one-fourth to one-third of the animal’s total length. This proportion is much higher for males than females. The snout is blunted and squarish. It may project up to 1.5 m beyond the tip of the lower jaw. The lower jaw is very narrow and weak and disproportionately small.
On the back of the animal is a clear hump, but no fin. It is located about two-thirds of the way back from the tip of the snout, and behind this are several smaller humps or knuckles. The dorsal hump and knuckles are clearly seen when a Sperm Whale arches to begin a dive. The skin may appear wrinkled, especially from behind the head. The flippers are short, but the tail is large and deeply notched. The Sperm Whale’s skin is up to 35 cm thick. This is the thickest skin of any animal.
The overall colour of Sperm Whales can be dark brown, grey or black. The belly and front of the head may be light grey. The blowhole is located at the front of the head on the left.
Size: Adults, Sperm Whale males grow much larger than females. The lengths attained by Sperm Whales are said to be 18 to 20 m for males and 12 to 13 m for females. Males may weigh from 45 to 70 tons, whilst females weigh up to 20 tons. Calves at birth, 4 m long.
Appearance At Sea: The fundamental social unit is a group of 20-30 consisting of maturing females and nursing calves. Bachelor herds are smaller, with around 20 younger males, and harem herds have not more than 80 adults and young.