SPERM WHALES – Physeteridae



The family of sperm whales contains the largest toothed whale—the giant sperm whale—and two smaller toothed whales. All are dark gray above, lighter gray on the belly, and have erupted (visible) teeth only in the lower jaw. Although these animals range in size and weight from 9 feet (2.7 meters) and 600 pounds (270 kilograms), to 60 feet (18.3 meters) and 125,000 pounds (57,000 kilograms), they have other physical features in common.

All members of this family have a spermaceti (spur-mah-CEEtee) organ in their forehead. This produces a waxy substance called spermaceti. At the animal’s body temperature, it is a clear yellowish liquid. After processing, it becomes a white waxy solid. It was prized in the 1800s and 1900s for making smoke-free candles and soap and as a way to waterproof cloth (called oilskins). Later it was used in cosmetics, ointments, as a lubricant for watches and machinery, and in automatic transmission fluid. Today it has been replaced by human-made oils and waxes.

The purpose of the spermaceti organ is not clear. Some scientists think that it helps the whale regulate its buoyancy, or ability to sink or float, during dives. Others believe that it is used to focus the sounds made for echolocation (eck-oh-lohKAY-shun) and communication. Echolocation involves making sounds that bounce off objects. Sense organs pick up the echo or reflected sound and use information about the timing, direction, and strength to determine the location of objects. Echolocation allows whales to find food in water so deep that there is no natural sunlight.

Members of the sperm whale family share other physical characteristics. Their heads are asymmetrical, meaning that if they were divided in half along the long axis of the body, the features in the right half would look different from the features in the left half. This is not common in mammals. As a result, a single S-shaped blowhole that allows the whale to breathe is located on the left side of the body. The left nasal passage is used for breathing, but the right one is narrower and is thought to be used to produce sounds.


Members of this family are found in oceans worldwide.


These are deep-water whales, living in water over 3,300 feet (1,000 meters) deep. Smaller species may live in slightly shallower water.


Sperm whales eat mainly squid, although they will also eat fish, crabs, and octopus that live on or near the ocean bottom.


Sperm whales appear to be very social, communicating through a series of clicks, whistles, and similar sounds. It appears as if each whale has a personal identification sound called a coda, that it makes when it meets other whales. These animals live in small groups. The composition of the group with regard to age, gender, and size changes as these animals age.

Almost nothing is known about reproduction in the smaller species of this family. Female giant sperm whales give birth about every five years after a pregnancy that lasts between fourteen and sixteen months. Mothers and calves have strong social bonds, and calves nurse for many years after birth.


Sperm whales were hunted for their spermaceti, blubber, and meat for many years. Minimal hunting still occurs. In parts of New Zealand, sperm whales form the basis of whale watching ecotoursism, where tourists observe whales without disturbing them.


Not enough is known about the smaller sperm whales to give them a conservation rating. Although there is some debate about population size, giant sperm whales are considered Vulnerable, facing a high risk of extinction, because of slow recovery from population declines that resulted from hunting.