About The Species

Sperm whales are the largest of the toothed whales and have one of the widest global distributions of any marine mammal species. They are found in all deep oceans, from the equator to the edge of the pack ice in the Arctic and Antarctic. They are named after the waxy substance, spermaceti, found in their heads. Spermaceti was used in oil lamps, lubricants, and candles. Sperm whales were a prime target of the commercial whaling industry from 1800 to 1987. Whaling greatly reduced the sperm whale population. Whaling is no longer a major threat and its population is still recovering. The sperm whale is listed as endangered under the Endangered Species Act and depleted under the Marine Mammal Protection Act. NOAA Fisheries and our partners are dedicated to conserving and rebuilding the sperm whale population. We use a variety of innovative techniques to study, protect, and rescue these endangered whales. We engage our partners as we develop regulations and management plans that encourage recovery, foster healthy fisheries, reduce the risk of entanglements, create whale-safe shipping practices, and reduce ocean noise.

Status

Commercial whaling from 1800 to the 1980’s greatly decreased sperm whale population worldwide. The International Whaling Commission placed a moratorium on commercial whaling in 1986. The species is still recovering, and its numbers are likely increasing.

Currently, there is no exact accounting of the total number of sperm whales worldwide. The best estimate of worldwide sperm whale population is between 300,000 and 450,000 individuals. Visit the most recent stock assessment report to view population estimates for sperm whales in U.S. waters.

Protected Status

ESA Endangered Throughout Its Range

CITES Appendix I Throughout Its Range

MMPA Protected Throughout Its Range

MMPA Depleted Throughout Its Range

Appearance

Sperm whales are mostly dark grey, though some whales have white patches on the belly. Sperm whales are the only living cetacean that has a single blowhole asymmetrically situated on the left side of the crown of the head. Their heads are extremely large, accounting for about one-third of total body length. The skin just behind the head is often wrinkled. Their lower jaw is narrow and the portion of the jaw closest to the teeth is white. The interior of the mouth is often bright white as well. There are between 20 and 26 large teeth in each side of the lower jaw. The teeth in the upper jaw rarely break through the gums. Sperm whale flippers are paddle-shaped and small compared to the size of the body, and their flukes are triangular. They have small dorsal fins that are low, thick, and usually rounded.

Behavior and Diet

Sperm whales hunt for food during deep dives that routinely reach depths of 2,000 feet and can last for 45 minutes. They are capable of diving to depths of over 10,000 feet for over 60 minutes. After long, deep dives, individuals come to the surface to breathe and recover for approximately nine minutes. Because sperm whales spend most of their time in deep waters, their diet consists of many larger species that also occupy deep ocean waters. This includes squid, sharks, skates, and fish. Sperm whales can consume about 3 to 3.5 percent of their body weight per day.

Where They Live

Sperm whales inhabit all of the world’s oceans. Their distribution is dependent on their food source and suitable conditions for breeding, and varies with the sex and age composition of the group. Sperm whale migrations are not as predictable or well understood as migrations of most baleen whales. In some mid-latitudes, sperm whales seem to generally migrate north and south depending on the seasons, moving toward the poles in the summer. However, in tropical and temperate areas, there appears to be no obvious seasonal migration.

Lifespan & Reproduction

Female sperm whales reach sexual maturity around 9 years of age when they are roughly 29 feet long. At this point, growth slows and they produce a calf approximately once every five to seven years. After a 14 to 16-month gestation period, a single calf about 13 feet long is born. Although calves will eat solid food before one year of age, they continue to nurse for several years. Females are physically mature around 30 years and 35 feet long, at which time they stop growing. For about the first 10 years of life, males are only slightly larger than females, but males continue to exhibit substantial growth until they are well into their 30s. Males reach physical maturity around 50 years and when they are 52 feet long. Unlike females, puberty in males is prolonged, and may last between ages 10 to 20 years old. Even though males are sexually mature at this time, they often do not actively participate in breeding until their late twenties. Most females will form lasting bonds with other females of their family, and on average 12 females and their young will form a social unit. While females generally stay with the same unit all their lives in and around tropical waters, young males will leave when they are between 4 and 21 years old and can be found in "bachelor schools,” comprised of other males that are about the same age and size. As males get older and larger, they begin to migrate toward the poles and slowly bachelor schools become smaller; the largest males are often found alone. Large, sexually mature males that are in their late 20s or older will occasionally return to the tropical breeding areas to mate.

Threats

Vessel Strikes Inadvertent vessel strikes can injure or kill sperm whales. Few vessel strikes to sperm whales have been documented, but vessel traffic worldwide is increasing, which increases the risk of collisions. Additionally, since sperm whales spend long periods, typically up to 10 min “rafting” at the surface between deep dives, this behavior makes them more vulnerable to vessel strikes. Entanglement Sperm whales can become entangled in many different types of fishing gear, including trap lines, pots, and gillnets. Once entangled, they may swim for long distances dragging attached gear, potentially resulting in fatigue, compromised feeding ability, or severe injury. These conditions can lead to reduced reproductive success and death. Sperm whales have also been documented to remove fish from longline gear, a behavior known as “depredation.” They do this by using their long jaw to create tension on the line, which snaps fish off the hooks. In addition, scientists think that this behavior may be learned between individuals. Depredation sometimes results in injury or entanglement. Ocean Noise Underwater noise pollution can interrupt the normal behavior of sperm whales, which rely on sound to communicate. As ocean noise increases from human sources, communication space decreases—the whales cannot hear each other, or discern other signals in their environment as they used to in an undisturbed ocean. Different levels of sound can disturb important activities, such as feeding, migrating, and socializing. Mounting evidence from scientific research has documented that ocean noise also causes marine mammals to change the frequency or amplitude of calls, decrease foraging behavior, become displaced from preferred habitat, or increase the level of stress hormones in their bodies. If loud enough, noise can cause permanent or temporary hearing loss. Marine Debris Sperm whales can ingest marine debris, as do many marine animals. Debris in the deep scattering layer where sperm whales feed could be mistaken for prey and incidentally ingested, leading to possible injury or death. Climate Change The effects of climate and oceanographic change on sperm whales are uncertain, but both can potentially greatly affect habitat and food availability. Site selection for whale migration, feeding, and breeding for sperm whales may be influenced by factors such as ocean currents and water temperature. Increases in global temperatures are expected to have profound impacts on arctic and subarctic ecosystems, and these impacts are projected to accelerate during this century. However, the feeding range of sperm whales is likely the greatest of any species on earth, and, consequently, sperm whales are likely to be more resilient to climate change than species with narrower habitat preferences. Oil Spills and Contaminants The threat of contaminants and pollutants to sperm whales and their habitat is highly uncertain and further study is necessary to assess the impacts of this threat. Little is known about the possible long-term and transgenerational effects of exposure to pollutants. Marine mammals are considered to be good indicators for concentrations of metal and pollutant accumulation in the environment due to their long lifespan and (in some cases) position near the top of marine food webs.

Scientific Classification