Sperm Whale: An Endangered Species Profile

Sperm whales (Physeter macrocephalus) are truly giants of the ocean. As the largest of the toothed whales, these massive marine mammals can reach over 60 feet in length and weigh up to 45 tons. Sperm whales have a distinctive block-shaped head and wrinkled skin. Their name comes from spermaceti, a milky-white waxy substance found in their heads. In the past, spermaceti was used to make oil lamps, lubricants, and candles.

Sperm whales inhabit all the world’s oceans from the equator to the polar edges. They dive to dark ocean depths over 6,500 feet to hunt squid, sharks, and deep-sea fish. After long 45-minute dives, they return to the surface for air.

Due to extensive whaling from 1800-1987, sperm whale populations plummeted. They are now endangered and still recovering. Commercial whaling has ended. However, sperm whales still face modern threats. They include ship strikes, fishing gear entanglements, ocean noise, and climate change impacts.

NOAA Fisheries is dedicated to the conservation and recovery of sperm whales. Through regulations, management plans, research, and rescue programs, NOAA protects these endangered marine mammals. Public education and partnerships also help safeguard sperm whales for the future.

With ongoing efforts to study and protect sperm whales, there is hope these majestic giants will thrive again in our oceans.

About Sperm Whales

Description and Appearance

Sperm whales have a very distinct and large appearance that makes them unmistakable. Their heads take up a third of their total body length and have a unique square, box-like shape. Inside their big heads is the spermaceti organ. This organ contains a waxy oil that gives sperm whales their name. Their large heads taper down to a short, undershot, narrow lower jaw. This gives sperm whales a triangular shape.

The skin behind the head is often wrinkled and compressed. Sperm whales are mostly dark gray, though some have white patches on their bellies. Their flippers are paddle-shaped and relatively small compared to their large size. Sperm whales have a small, low dorsal fin that is thick and usually rounded at the top. Their tail flukes are wide and triangular in shape.

One unique feature is the sperm whale’s single blowhole located on the left side of their head crown. When surfacing to breathe, they expel a bushy blow angled forwards and to the left. Sperm whales have 20 to 26 conical teeth on each side of their narrow lower jaw. But their short, undershot upper jaw rarely has teeth.

Given their immense size, sperm whales are the loudest animals on Earth. They have wide heads. Their heads contain a structure called the monkey lips/monkey throat used to focus and project loud communicative clicks. Sperm whales use these powerful vocalizations to echolocate and communicate with other whales.

Behavior and Diet

Sperm whales spend most of their time in the deep, dark waters of the open ocean. They dive to depths of over 6,500 feet for up to 45 minutes to hunt for food. Sperm whales are capable of diving even deeper, to over 10,000 feet, for over an hour.

Their diet consists mainly of large squid but also includes sharks, skates, and deep-sea fish. Sperm whales will consume around 3-3.5% of their body weight in prey each day – a huge amount considering their massive size.

To locate food in the lightless depths, sperm whales use echolocation. They emit a focused beam of clicks directed forward through their head. The clicks bounce off objects and return echo information about the distance and shape of prey items. Sperm whales may also passively listen for sounds from moving prey.

After making long, deep forays to find patches of food, sperm whales spend about 10 minutes recovering at the surface. They breathe heavily to re-oxygenate their blood and rest before diving again. Sperm whales are often seen lying motionless just under the surface in a head-down tilted orientation.

Sperm whales migrate based on age and sex. Adult females and young sperm whales live in tropical waters year-round. In spring and summer, adult males migrate long distances towards the poles. Then, the males return to warmer tropical waters in winter to mate with females. Compared to other whales, sperm whales are less migratory overall.

Sperm whale social groups differ by age and sex. Females form lasting bonds and live in tropical waters with their offspring in groups of around a dozen. Males leave these nursery groups and join “bachelor schools” with similar-aged males. Older lone males migrate between the poles and tropics.

Read Also: Why Do Sperm Whales Sleep Vertically?

Habitat and Range

Sperm whales have an extensive habitat range. They live in all the world’s oceans, from equatorial to polar waters. These whales generally prefer offshore, deep waters between 60° N and 60° S latitudes. Sea surface temperatures stay above 15°C in these areas. Their distribution corresponds with access to food sources and suitable breeding conditions.

A world map depicts the approximate global range of sperm whales.

In tropical and temperate waters, sperm whales are found year-round. This is where adult females and young whales live in nursery groups. Some male sperm whales migrate seasonally into colder waters at higher latitudes. They have been observed as far north as the Arctic Ocean and as far south as the Antarctic ice edge.

Sperm whales are often associated with sharp increases in depth. These areas include continental shelves and canyons. Upwelling in these spots brings nutrients and aggregates prey. They can be found anywhere from several miles to over 100 miles offshore as long as deep waters are nearby.

While sperm whales have a continuous worldwide distribution, their population density varies by region. Higher densities are found in the North Atlantic Ocean, North Pacific Ocean, and the Northern Indian Ocean. The North Pacific hosts the largest known population.

The sperm whale’s extensive range and habitat preference for offshore waters has protected them somewhat from human activity. But as fisheries expand farther offshore and technology enables more exploration of the deep sea, sperm whales may lose their refuge.

Lifespan and Reproduction

Sperm whales have a long lifespan that can exceed 70 years for females. They also have an extended breeding cycle compared to many other whales.

Females reach sexual maturity around 9 years old when they are about 30 feet long. At this point, their growth slows and they begin producing a calf about once every 5-7 years. The gestation period is 14-16 months, after which a single calf is born tail first. Newborn calves already measure up to 13 feet long.

Calves continue to nurse for several years, even after beginning to eat solid food before age one. Females grow to around 35 feet in length and are considered physically mature by age 30 when their growth stops.

Males go through an extended puberty from ages 10-20 years old. Though sexually mature during this time, males do not actively participate in breeding until their late 20s. Males continue growing into their 30s, reaching about 52 feet long when fully mature.

Female sperm whales spend their entire lives in tropical waters with their birth group. Males eventually leave this natal group between ages 4-21. Young males join “bachelor schools” with similarly aged males. As males age and grow larger, their groups shrink in size. The largest adult males over 30 years old are often encountered alone, having left group living.

The oldest males will migrate back to breed with females in tropical areas during winter months. Competition for breeding access to female groups drives males’ transition from social to solitary living as they age.

Threats and Conservation Issues

Commercial whaling is now banned. However, sperm whales still face many threats from human activities. Their endangered status means sperm whales are at risk of extinction. Ongoing conservation efforts aim to protect them and support the recovery of their populations.

Vessel Strikes

Collisions with ships and boats pose an increasing threat as vessel traffic rises worldwide. Sperm whales spend up to 10 minutes resting at the surface between deep dives. During these periods they are vulnerable to being struck, often sustaining fatal injuries. Their preference for shipping lane areas exacerbates the vessel strike hazard.

Entanglement in Fishing Gear

Fishing gear like gillnets, traps, and buoy lines can entangle sperm whales while they are diving and foraging. Entangled whales may swim for long distances while attached to gear, leading to exhaustion, starvation, and severe injuries. This can impact their reproduction and survival.

Sperm whales are also at risk from depredation while taking fish off longline gear. This behavior raises their chances of entanglement in fishing equipment.

Ocean Noise

Human-generated noise from ships, sonar systems, oil and gas exploration, and coastal construction interferes with sperm whale communication and echolocation. Noise levels disturb vital behaviors like feeding, migrating, and socializing. With mounting evidence of impacts, managing ocean noise is a key concern.

Different noise levels can disturb sperm whales. Loud sounds may disrupt feeding, migrating, and socializing. Scientific research shows noise causes other effects, too. Marine mammals may change their call frequency or volume. They might decrease foraging time. Noise can displace mammals from preferred habitats. It can also increase their stress hormones. If loud enough, noise can permanently or temporarily damage hearing.

Additional Threats

Other threats sperm whales face include ingestion of marine debris while feeding, climate change effects on their prey and habitat, oil spills and pollution, overfishing of their food sources, and past mass deaths from whaling. Ongoing research on population trends and emerging threats helps guide conservation priorities.

Conservation Efforts

Many conservation measures are in place to protect sperm whales and promote the recovery of their populations. These include:

Recovery Planning: The ESA requires NOAA Fisheries to develop and implement recovery plans for listed species like the sperm whale. The goal is to address threats and restore populations to sustainable levels. Major actions recommended include reducing vessel collisions and fishing gear entanglements, protecting habitat, minimizing vessel disturbance, continuing the whaling ban, monitoring abundance, maximizing disentanglement efforts, and acquiring data from dead whales.

Habitat Protection: Marine sanctuaries, reserves, and protected areas help safeguard sperm whale habitats. They protect key areas from disruptive activities.

Reducing Bycatch: Fishing regulations, modifications to gear, and fishery closures help decrease entanglements and mortality.

Disentanglement Networks: Groups authorized to rescue entangled sperm whales minimize injury and enhance survival chances.

Vessel Speed Restrictions: Reduced ship speeds in areas with high sperm whale densities help prevent deadly collisions.

Noise Management: Guidelines and zoning reduce noise impacts on whales from sources like Navy sonar exercises and seismic surveys.

UME Investigations: Unusual mortality events are investigated to identify causes and prevent future mass deaths. Sperm whales have been part of declared UMEs in the past.

Outreach and Education: Public awareness programs foster stewardship and motivate participation in conservation.


Sperm whales are amazing, giant marine mammals that are vital to ocean ecosystems. Their huge size and deep diving let them hunt prey in extreme environments across the world’s deep oceans. But centuries of whaling greatly reduced sperm whale populations.

Although commercial whaling has ended, sperm whales remain endangered by modern threats like ship strikes, fishing gear entanglements, and ocean noise. These hazards obstruct the recovery of this species.

NOAA Fisheries and partners are working to protect sperm whales through many conservation efforts. These include recovery planning, habitat protection, disentanglement networks, noise regulation, and public education.

While their populations slowly grow, sperm whales have the potential to thrive again with ongoing safeguards and responsible stewardship. The majestic sperm whale’s future remains tied to the health of our oceans. As top predators, their well-being reflects the state of marine ecosystems we all rely on.

With persistent, thoughtful management, the outlook for sperm whales can be positive. Dedicated conservation offers hope that these magnificent giants will once again flourish in our oceans.

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NOAA Fisheries. (Updated on on 01/30/2023). Sperm Whale. www.fisheries.noaa.gov.

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