Illustration Credit: Uko Gorter
Common name: Sperm whale
Scientific name: Physeter macrocephalus
Length as an adult: Adult males grow to be about 50-60 feet (17-20 m) long. Females are smaller, about 33-40 feet (11-13 m) long.
Weight as an adult: Males about 40-50 tons (176,000 – 220,000 kg), females about 14-18 tons (61,600 – 79,200 kg).
Length and weight at birth: A newborn sperm whale is around 13 feet (4 meters) in length and weighs approximately 1 ton (2,2000) kilograms or more. They grow very fast.
Length of pregnancy: Gestation lasts about 14 to 16 months.
Sperm whales are found in all oceans of the world. The males, alone or in groups, are found in higher latitudes. Females, calves, and juveniles remain in the warmer tropical and sub-tropical waters of the Pacific, Atlantic, and Indian Oceans year round.
Likelihood of being seen on a whale watch in Massachusetts coastal waters: highly unlikely
Preferred food: squid, octopus and fish
Unusual characteristics: It has a giant block shaped head which can measure up to 1/3 of the whales overall size and length full with oil.
Appearance: The head of the sperm whale is blunt and squared off, and has a small, underslung jaw. The head is also large, and makes up to 1/3 the total body length and more than 1/3 of its mass. A single blowhole is located forward on the left side of the head, and the blow, which is bushy, is projected forward rather than straight up as it is with other whales. Its body has a wrinkled, shriveled appearance, particularly behind the head.
General information: The sperm whale is the largest odontocete, or toothed whale. It has been portrayed frequently in art and literature as a symbol of the great whales, and is best known as the leviathan Moby-Dick in Melville's novel by that name. Unique in appearance, the sperm whale seems to have social characteristics that, to date, also appear to be unique among whales. Sperm whales are among the deepest diving cetaceans, and are found in all oceans of the world. Females and their young travel in permanent units, whereas the much larger males rove between breeding and feeding grounds, as well as among groups of females when breeding.
Unusual habits: When confronted with predators individuals are known to cluster together into defensive formations.
Population status: The best estimate, between 200,000 and 1,500,000 sperm whales, is based on extrapolations from only a few areas that have useful estimates.
Threats: Killer whales have been seen attacking sperm whales, but usually unsuccessfully. Pilot whales are also known to harass them. Other potential predators of younger animals include large sharks.
Human impact: These whales were one of the most heavily exploited of all the world’s whales, although they are still relatively abundant.
American Cetacean Society www.acsonline.org
Society for Marine Mammalogy www.marinemammalscience.org
Carwardine, Mark. Whales, Dolphins, and Porpoises. London: Dorling Kindersley, 1995.
Prepared by: Joseph Delgado Ortiz