Physeteroidea

Sperm whale ( Physeter catodon ), mother with calf

The sperm whales ( Physeteridae ) are a family of toothed whales. Addition to the actual sperm whale It also includes the two types of dwarf sperm whales.

Features

Sperm whales are significantly different in size. While the actual sperm whale can reach 20 meters in length and 50 tons in weight, the dwarf sperm whales are only up to 3.4 meters long and 400 kilograms. Common to them is the excessively large forehead with the spermaceti organ. Teeth are only on the lower jaw present, the unpaired nostril is located on the left side of the skull - in the dwarf sperm whales at the apex and in the actual sperm whale on the front head.

System

Traditionally, the sperm whales are classified to the toothed whales. Some phylogenetic analyzes, however, see it as a sister group of the baleen whales, and thus more closely related to these than with the other toothed whales. However, this is controversial. The sperm whale family is placed in a superfamily Physeteroidea with some extinct whales from the main line of sperm whales (eg Livyatan melvillei ).

Within the sperm whales two genera are distinguished with three types:

• Genus Physeter Sperm whale ( Physeter catodon )

• Little sperm whale ( Kogia simus )
• Dwarf sperm whale ( Kogia breviceps )

Due to large differences in the proportions, the physique and the way of life the dwarf sperm whales are sometimes classified in a separate family ( Kogiidae ).