The largest of the toothed whales, Sperm whale males can grow to 18.5m (60ft) and 50 tons, females reach only 13m and weight a of 18 tons, much smaller than males. The head is around a third of the body size with small eyes and a single blowhole on the left side of the slope of the forehead. Lips are marbled outside the mouth. They have 18-25 large conical teeth in each side of the lower jaw. The 10-16 teeth in the upper jaw rarely erupt through the gums. The body is olive/ dark brown to blue-grey often with irregular rippled or corrugated skin. There is a series of knuckle- like ridges for a fin and they have small stubby flippers. Flukes are small and broad with rounded tips.
Squid is the main food of Sperm whales. They throw their flukes high in the air when they dive and the blow is forward and to the left. Dives can be as deep as 1000m and last for over an hour, diving deeper and for longer than any other whale.
They are believed to live up to 70 years. Calves between 3.7 and 4.4 m long and weighing around 900kg are born after a gestation of 16 months. Their mother feeds them for up to 24 months.
These whales are found worldwide from the Arctic to Antarctica. Sperm whales sighted in the deep South Atlantic off the Falkland Islands are very likely to be males moving south for the austral summer. Females and juveniles rarely come further south than 40°.
Their IUCN Conservation status is 'vulnerable'.
In the Falklands the Blue whale is classed as a 'regular' cetacean. The Falkland Islands Marine Mammals Ordinance 1992 protects all marine mammals in all waters from the coast to the edge of the economic exclusion zone.
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