Sperm Whale Facts | New Zealand Wildlife Guide

Sperm whales (Physeter catodon) are the largest toothed whales in the world. The Greek word “Physeter” means “blower,” referencing the whale’s habit of blowing a spout of vapor when it breaks the ocean’s surface to exhale. The word “catodon” in Greek means “lower tooth” which likely relates to the whales’ long row of teeth in their lower jaw. The sperm whale’s vernacular name may reference the white, waxy spermaceti produced in the whale’s head, which was once used in candles and ointments, though some suggest it might reference the male’s large, retractable penis.

Physical Characteristics

• Males average about 50 feet in length and 40 tons in weight, and the much smaller female averages 36 feet and 22 tons in weight.
• They have an enormous square head that makes up one-third of their total body length and houses an organ filled with spermaceti. This organ is thought to focus and reflect sound or function as a cooling organ that diminishes the whale’s volume and buoyancy during prolonged dives.
• Sperm whales have the largest brain of any mammalian, weighing approximately 20 pounds.
• They also have the largest gullet of any cetacean, large enough to swallow a human.
  The lower jaw is long and narrow and appears small compared to the overall size of the head. The lower jaw holds a long row of 18 to 28 functional teeth on either side, while the upper jaw has only a small number of weak, nonfunctioning teeth.
• They don’t have a true dorsal fin, however, most have a series of knobs or lumps on their backs.
• A sperm whale’s coloration is generally dark gray or brownish (pure white specimens like the mythical Moby Dick have been seen, but rarely), and much of the body surface is covered with crenulations.
• Unlike all other cetaceans, the sperm whale’s S-shaped blowhole sits left of center at the foremost upper point of their snout.
• Their characteristic blow shoots out in a forward direction and to the left and can indicate the direction the animal is swimming.
• The flippers are short and stubby, and the tail fluke, which measures between 13 and 15 feet wide, is strong and square in shape.
• The blubber layer of the giant sperm whale is quite thick, up to 14 inches.
  
  

Habitat

While sperm whales are found in all oceans, they frequent temperate and tropical waters, though adult males populate higher latitudes such as Greenland. They make their habitat at depths of more than 3,000 feet, with cool, nutrient-rich upwellings and plentiful squid. Their migration range depends on the season, as well as their social status and sexual hierarchy. Built to swim in the depths of the oceans, sperm whales risk getting stranded if they roam too close to the shore.

Feeding Habits

Sperm whales consume approximately three percent of their body weight every day feeding primarily on squid, including the giant, deep-sea species. In addition to squid, they also prey on skates, sharks and a variety of deepwater fish. These creatures are champion divers and are known to have reached depths of at least 10,000 feet. While most dives are only about ten minutes in duration, they are able to stay underwater for more than an hour.

Behavior & Communication

A sperm whale will give 20 to 70 blows when it breaks the water’s surface before descending into the ocean depths. The blows create a long spout of vapor and mucous foam produced by the sinuses. Sperm whales amble along at six miles-per-hour but can reach speeds of up to 19 miles-per-hour if provoked. They are one of the most aggressive species of whales, battling giant squids to the death, and sinking whalers’ rowboats when antagonized.

Sperm whales use echolocation by making a series of clicking sounds and are also able to make a host of other noises, including chirps, whistles, groans, squeaks, yelps, wheezes, and pings. Their voices belt out in booming tones, audible from miles away with underwater recording equipment. When sperm whales meet, they greet each other with a repetitive clicking sound, which can be over 40 in number. This sequence is called a sperm whale’s “coda.”

Sperm whales journey long distances, migrating along the same paths as their prey. Adult males have the largest range, spanning from Antarctica to the Bering Sea, while adult females and their calves keep to more tropical waters.

Reproduction

Highly social creatures, sperm whales commonly travel in family groups of 30 or so individual whales. Sperm whales also form pods of 100 or more members based on age and sex. These pods usually consist of sexually inactive males in “bachelor schools,” or adult females with young in “nursery schools.” Older males typically live on their own until joining females in the tropics during the breeding season. Females reach sexual maturity at eight to eleven years of age, while and males mature later at approximately ten years of age. Males do not actually mate until about 25 years of age when they achieve the necessary social status to join a breeding school.

The peak mating season takes place in the spring in both Northern and Southern hemispheres, and most calves are born in the fall. During the mating season, schools of one to five dominant males, and a number of females and males of different ages are created. Next, a fierce competition takes place over breeding rights with females. Male sperm whales battle each other, and many bear scars on their heads as a result of these fights. In the end, only 10 to 25 percent of adult males are able to breed.

Mating is polygamous within this species. The gestation period lasts between 14 and 16 months, after which time, a single calf is born. Calves measure between 12 and 14 feet at birth, and nurse for up to two years. The maximum known lifespan for the sperm whale is 77 years.

Conservation

In years past, the sperm whale was the largest target of commercial whaling. Many were hunted by American vessels based in New England ports, and later from San Francisco ports—at one time, sperm whales comprised 40 percent, by weight, of the total catch of all species of whales. The meat of the whale is not generally consumed; rather, spermaceti is gathered, and the bones and teeth of the whale are used to craft scrimshaw, colorful, ornamental carvings. The head of the sperm whale contains between three and four tons of spermaceti, a substance once used as a lubricant for fine machinery, a component of automatic transmission fluid and an ingredient in making ointments and fine, smokeless candles.

Sperm whales once frequented the Gulf of Mexico, but because of commercial whaling practices, are now rarely seen. Around the world, however, the population of sperm whales has become more stabilized in comparison to other whales. Though the sperm whale continues to be endangered, there are now more sperm whales than any other great whale.

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