Classification: 

During the days of commercial whaling, sperm whales were so named because when the head was cut open it was found to contain a milky white substance, and the whalers thought the large square head was a huge reservoir for sperm.

Additionally, an intestinal secretion called ambergris is found in sperm whales which was used as a fixative in the perfume industry and was at one time worth more than its weight in gold.

 

 

Appearance: 

The sperm whale belongs to the suborder of toothed whales and dolphins (odontocetes) and is one of the easiest whales to identify at sea. The angled bushy blow is distinctive from a distance as a sperm whale has a single blowhole on the left side.

Near the front of the head and close up, its enormous square-shaped head and wrinkly skin are unmistakable.

The skin is dark grey or brownish grey, with white markings around the lower jaw and underside.

The sperm whale's huge head, which is up to 1/3 of its overall body length, houses the heaviest brain in the animal kingdom.

They have between 40-52 teeth in their long, narrow lower jaw.

These are thick and conical, and can grow to 20cm long and weigh 1kg each.

The sperm whale has a relatively short, stubby flippers and a low hump instead of a dorsal fin, with 'knuckles' stretching from the hump along their backs to their triangular tail flukes, which are raised when diving.

Most females, but few males, have calluses on the dorsal hump.

 

 

Behaviour: 

The sperm whale is one of the deepest diving mammals in the world.

Typically it makes dives of up to 400 m, but can reach depths of up to 2-3km.

It is thought to be able to hold its breath for up to two hours, although 45 minutes is the average dive time. Some sperm whales have scars on their bodies caused by giant squid tentacles during fights.

Although sperm whales are known to eat a wide variety of sea creatures their major prey items are deep-water squid which they are believed to 'catch' by the suction method of eating.

Sperm whales can be quite gregarious and are known to breach, spyhop and lobtail.

A sperm whale spends most of its life in either 'nursery schools' (adult females with young) or 'bachelor schools' (males between seven and 27 years of age) although older males tend to live on their own or in very small groups and join nursery schools during the breeding season.

The only natural predator of the sperm whale is the orca and even then most attacks are not thought to be fatal. During such attacks however, the females show defensive behaviour of calves by creating a ring with the calves in the centre – called a 'marguerite'.

These rings may have their heads or tails on the outside.