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. The spermaceti is an oil sac that helps the whales focus sound. Spermaceti was used in oil lamps, lubricants, and candles. Sperm whales were a primary target of the commercial whaling industry from 1800 to 1987, which nearly decimated all sperm whale populations. While whaling is no longer a major threat, sperm whale populations are 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 sperm whale populations. 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.
Commercial whaling from 1800 to the 1980s greatly decreased sperm whale populations worldwide. The International Whaling Commission placed a moratorium on commercial whaling in 1986. The species is still recovering, and its numbers are likely increasing.
Visit the most recent stock assessment report to view population estimates for sperm whales in U.S. waters.
Sperm whales are mostly dark grey, though some whales have white patches on the belly. They 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 their 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 on 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 several minutes before initiating their next dive.
Because sperm whales spend most of their time in deep waters, their diet consists of species such as squid, sharks, skates, and fish that also occupy deep ocean waters. 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 baleen whales. Some populations appear to have different migration patterns by life history status, with adult males making long oceanographic migrations into temperate waters whereas females and young staying in tropical waters year-round.
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 reach their maximum length and are physically mature around 30 years old at which they measure up to 35 feet long.
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 approximately 52 feet long. Unlike females, puberty in males is prolonged, and may last between the ages of 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 social unit in and around tropical waters their entire lives, young males will leave when they are between 4 and 21 years old and can be found in "bachelor schools,” composed of other males that are approximately the same age and size. As males get older and larger, they begin migrating toward the poles. As a result, bachelor schools become smaller and 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.
Vessel strikes can injure or kill sperm whales. Few vessel strikes of 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 minutes) “rafting” at the surface between deep dives, they are more vulnerable to vessel strikes.
Entanglement in Fishing Gear
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, reduced reproductive success, severe injury, or 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 shakes fish off the hooks. In addition, scientists think that this behavior may be learned between individuals. Depredation increases a sperm whale’s likelihood of injury or entanglement while maneuvering around boats and fishing gear.
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 activities such as feeding, migrating, and socializing. Mounting evidence from scientific research has documented that ocean noise can also cause 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.
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.
The effects of climate and oceanographic change on sperm whales are uncertain, but both can potentially affect habitat and food availability. Whale migration, feeding, and breeding locations 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 expected to be more resilient to climate change than species with more restrictive 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 effects 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.
In the Spotlight
The sperm whale has been listed as endangered under the Endangered Species Act since 1970. This means that the sperm whale is in danger of extinction throughout all or a significant portion of its range. NOAA Fisheries is working to protect and recover this species.
Recovery Planning and Implementation
Under the ESA, NOAA Fisheries is required to develop and implement recovery plans for the conservation and survival of listed species. The Recovery Plan for the sperm whale was published in December 2010. The plan’s goal is to delist the species, with an interim goal of down-listing its status from "endangered" to "threatened."
The major actions recommended in the plan are:
- Reduce or eliminate injury or mortality caused by vessel collisions
- Reduce or eliminate injury and mortality caused by fisheries and fishing gear.
- Protect habitats essential to the survival and recovery of the species
- Minimize effects of vessel disturbance
- Continue international ban on hunting and other directed take
- Monitor the population size and trends in abundance
- Maximize efforts to free entangled or stranded sperm whales
- Acquire scientific information from dead specimens
NOAA Fisheries is working to minimize effects from human activities that are detrimental to the recovery of sperm whale populations in the U.S. and internationally. Together with our partners, we undertake numerous activities to support the goals of the sperm whale recovery plan. The ultimate goal is to delist the species.
Efforts to conserve sperm whales include:
- Protecting habitat
- Reducing bycatch
- Rescue, disentanglement, and rehabilitation
- Eliminating the harassment of animals through education and enforcement
Addressing Ocean Noise
Underwater noise may threaten sperm whales by interrupting their normal behavior and driving them away from areas important to their survival. Mounting evidence suggests that exposure to intense underwater sound may cause injury to sperm whales resulting in loss of hearing, or possibly stranding and ultimately death. NOAA Fisheries is investigating sound production and hearing in marine animals, as well as the effects of sound on whale behavior. In 2018, we revised technical guidance for assessing the effects of anthropogenic sound on marine mammals’ hearing.
Overseeing Marine Mammal Health and Stranding Response
We work with volunteer networks in all coastal states to respond to marine mammal strandings including all whales. When stranded animals are found alive, NOAA Fisheries and our partners assess the animal’s health and determine the best course of action. When stranded animals are found dead, our scientists work to understand and investigate the cause of death. Although the cause often remains unknown, scientists can sometimes attribute strandings to disease, harmful algal blooms, vessel strikes, fishing gear entanglements, pollution exposure, and underwater noise. Some strandings can serve as indicators of ocean health, giving insight into larger environmental issues that may also have implications for human health and welfare.
Marine Mammal Unusual Mortality Events
Sperm whales have been part of a declared unusual mortality event in the past. Under the Marine Mammal Protection Act, an unusual mortality event is defined as "a stranding that is unexpected; involves a significant die-off of any marine mammal population; and demands immediate response." To understand the health of marine mammal populations, scientists study unusual mortality events.
Educating the Public
NOAA Fisheries increases public awareness and support for marine mammal conservation through education, outreach, and public participation. We regularly share information with the public about the status of sperm whales, our research, and our efforts to promote their recovery.
The sperm whale was originally listed as endangered throughout its range on June 2, 1970 under the Endangered Species Conservation Act of 1969, the precursor to the Endangered Species Act of 1973. Sperm whales are also protected under the Marine Mammal Protection Act of 1972.
Key Actions and Documents
Incidental Take Authorization: U.S. Navy Hawaii-Southern California Training and Testing (HSTT) (2018-2025)
- Proposed Rule (2023)
- Notice of Receipt of Application for Revision to 7-Year Rule and LOAs
- Final 7-Year Rule (2020)
- Proposed 7-Year Rule (2019)
- Notice of Receipt of Application for 7-Year LOAs
Incidental Take Authorization: Lamont-Doherty Earth Observatory's Marine Geophysical Survey in the Puerto Rico Trench and slope of Puerto Rico
Incidental Take Authorization: Atlantic Shores Offshore Wind Bight, LLC's Marine Site Characterization Surveys off New Jersey and New York
Incidental Take Authorization: Vineyard Northeast, LLC's Marine Site Characterization Survey from Massachusetts to New Jersey
NOAA Fisheries conducts research on the biology, behavior, and ecology of the sperm whale. The research is used to inform management decisions and enhance recovery efforts for this endangered species.
Determining the number of sperm whales in each population—and whether a stock is increasing or decreasing over time—helps resource managers assess the success of enacted conservation measures. Our scientists collect information and present these data in annual stock assessment reports.
NOAA Fisheries regularly uses genetic data to better understand population structure of marine mammals, including that of sperm whales. Acoustic research (the science of how sound is transmitted) increases our understanding of whale, dolphin, and fish behavior as well as the environmental soundscape; and enables the development of better methods to locate cetaceans using autonomous gliders and passive acoustic arrays.
Acoustics are used to monitor hearing levels and feeding behavior in sperm whales. We also study how underwater noise affects the way sperm whales behave, eat, interact with each other, and move within their habitat.
Currently, NOAA Fisheries’ goal is to re-examine the stock designations for every stock managed using molecular genetic data. We use the genetic data to determine patterns of relatedness within groups of sperm whales encountered at sea. These data shed light on the evolution of sociality at sea and the nature of social bonds in groups of free-ranging whales.
Sperm whales have been tagged in an effort to learn more about foraging behavior, movement patterns, and core home ranges.
Recent Science Blogs
Biological Opinion on the effects of the proposed construction of a cruise ship berth and…
Biological Opinion on 10 Fishery Management Plans in the Greater Atlantic Region and the New…
Endangered Species Act (ESA) Section 7(a)(2) Biological Opinion for City of Hoonah Marine…
Biological Opinion National Petroleum Reserve-Alaska Integrated Activity Plan Biological Opinion (AKRO-2020-01519)
Endangered Species Act Section 7(a)(2) Biological Opinion on the National Petroleum Reserve-Alaska…
Data & Maps
This mapping tool shows when and where specific whale, dolphin, and other cetacean species were…
Tracks the implementation of recovery actions from Endangered Species Act (ESA) recovery plans.