Sperm Whales

Sperm Whales

Endangered sperm whales are the largest toothed mammal in the world. Males are significantly larger. They are dark blue-gray to black in color. Males pale as they age. Sperm whales have a gigantic, square-shaped head with a slender lower jaw. Their head makes up one-third of their length. They do not have a dorsal fin. The head houses a large spermaceti organ filled with spermaceti oil that turns from liquid to solid as the water turns colder. Because a solid is generally heavier than a liquid, this "weight" in the whale's head allows it to dive deep to find food, up to 4,000 feet.

Males can reach 66 feet in length, though most are about 50 feet in length. Females are rarely longer than 40 feet in length. Male sperm whales weigh between 77,000 and 110,000 pounds; females weigh only one-third as much as males. Sperm whales can live up to 77 years.

They are found in all the oceans of the world, but concentrated in areas of plentiful food such as the coast of South America, the coast of Africa, the north Atlantic sea, the Arabian sea, the western north Pacific and near the equator. They feed on giant squid, schooling fish, seals and sharks. Sperm whales consume approximately one ton of food each day.

Sperm whales are found in mixed groups of 20 to 40 individuals including adult females, calves and juveniles. After weaned from their mother, juveniles leave their group to form juvenile schools. Females will return to a mixed group before reaching maturity while males form bachelor groups or become solitary. Sperm whales do not migrate over large distances as some other whale species do.

Sperm whales mate in the spring and have calves in the fall. A single calf is born after a 14 to 19 month gestation. Newborn calves weigh about 2,000 pounds and are about 13 feet in length.

In the past, sperm whales were hunted for their ambergris, a waxy oil substance. This oil was used for lighting fuel. Spermaceti oil was also used to make candles and lubricant.


Due to the danger of extinction facing many whale species, the IWC voted to suspend all commercial whale hunting beginning in 1986. Despite this international agreement to stop killing whales for their parts, several countries continued to kill whales and sell their meat and parts, including Norway, Iceland and Japan.

A loophole in the ban on commercial whaling allowed for the killing of large and medium whales for "scientific purposes." The ban also doesn't cover smaller whales like pilot whales, dolphins and porpoises. Iceland and Norway take whales within their own waters, otherwise known as exclusive economic zones. Japan conducts whaling in international waters, including in a whale sanctuary in the ocean off the Antarctic coast, despite the ban.

Whales are most often killed using a primitive weapon called a harpoon. The harpoon has a grenade attached that explodes when the harpoon enters the body of the whale. It can take a very long time for some whales to die which causes additional suffering and fear in these gentle animals. There is no humane way to kill a whale.

Despite international pressure and the best efforts of grassroots movements to ‘save the whales’ around the world, whaling continues to be a danger facing whales and their future here on earth.