Sperm whale

Main Characteristics

Sperm Whales are the largest of the toothed whales, they have a rather wrinkled and shriveled appearance. The body is evenly dark grey with a white upper lip and white patches on the belly. The head measures _^1/3 of the body length and is blunt and square. The dorsal fin is low and thick. The flippers are short and broad, the fluke can be 5m wide and is triangular in shape with a straight trailing edge. The single blowhole is located in the front left side of the head, creating a bushy, forward projected blow. The lower jaw is small and contains all the teeth. The 40-52 teeth are conically shaped and fit into sockets in the upper jaw. They were often used for carvings, known as scrimshaw.

Behaviour and Foraging

While foraging, Sperm Whales can dive as deep as 3000m and stay submerged for more than 2 hours. Between the dives they spend long times "rafting" at the surface.

The females form stable, long-term groups that stay in warmer, tropical waters year round. The males are solitary during their breeding prime and old age, but form "bachelor-groups" until they have reached maturity. They travel towards the productive oceans in higher latitudes to accelerate their growth, to be able to fight competitors during mating season. They usually occur in deeper waters and are rarely seen close to shore.

 Whaling and Population Size

There was a general reduction in the population size during the era that Sperm Whales were hunted or from 1712 until about 1983. The population is now considered to be stable. The selective killing of large mature males over many years is resulted in a declining birth rate. Because of long diving times it is harder to estimate the population of Sperm Whales than most other species. Estimated population size is 1.000.000 individuals. 

To learn more about Sperm Whales visit Wikipedia or The American Cetacean Society.