The sperm whale is one of the world's loudest and most recognizable animals and is well known because the species was the inspiration for Herman Melville's Moby Dick. Sperm whales are the largest of the toothed whales and have the heaviest and largest brain of any animal—marine mammals or otherwise—weighing up to 21 pounds.
While many believe the name "sperm whale" relates to their uniquely shaped head, the name actually originated in the early 19th century when early whalers believed the white oil found in the spermaceti organ of the whale's head was sperm. While that belief has since been disproven, the the name has stayed.
Continue reading to learn more about sperm whales, including where sperm whales hunt, where sperm whales live, what they eat, and more.
Interesting Sperm Whale Facts
Name: Sperm whale (Physeter macrocephalus)
Length: 53-66 feet (16-20 metres)
Weight: 88,000 - 12,000 pounds (40,000 - 55,000 kg)
Conservation status: Vulnerable
Diet: Mainly squid, but also octopi, megamouth sharks, rays and fish
Appearance: Dark grey, a single blowhole on the left side of their extremely large, unique block-shaped head with a rounded forehead that makes up one third of their total body length.
What do sperm whales eat?
It might surprise you to learn that sperm whales are one the world's loudest animals, and that they use their booming, loud sound as echolocation to hunt. Sperm whales are deep divers in the dark, deep ocean. Consequently, relying on sound to locate their prey is important to their hunting. Some believe these creatures can even kill their prey with their sound alone.
Sperm whales can eat up to two tons of food in one day, roughly 3% of their total body weight. It's estimated that sperm whale populations eat 91 million tons of food every year, and some estimates believe sperm whales alone eat more than 100 million tons of the world's squid population annually.
Sperm whales dive for food at depths of 2,000 feet (600 metres) for up to 45 minutes, then come back to the water's surface between dives to recover and breathe before plunging for their food again.
Some sperm whales can dive as deep 3,000 feet (915 metres) and can hold their breath for up to 90 minutes. Typical speed for a sperm whale is up 6mph but when hunting it can reach speeds up to 19mph.
Male sperm whales will occasionally attack killer whales when competing for food.
Sperm whale diet
With their huge gullet (the biggest of all whales) that can swallow a whole human, sperm whale diets consist of:
- skates (fish)
- squid and giant squid
Sperm whale hunting
The white waxy substance, spermaceti oil, which gave sperm whales their name is found in an organ in the heads of sperm whales.
While the purpose of the oil is not completely understood, there are two main theories for the use of the oil for the whales:
- The oil helps the whales with floatation when they are sleeping or recovering after long, deep dives
- The oil helps the whale focus on sound and echolocation
Regardless of the use of the oil for the whales, whale oil was a popular commodity for use in candles, soaps, lubricants, cosmetics and oil lamps that made sperm whales a target in the commercial whaling industry from 1800 to 1980s and destructive hunting practices almost wiped out all sperm whale populations. In fact, some estimates suggest that the total sperm whale population was reduced by 75% due to whale hunting.
Thankfully, since the 1980s, whaling has become less of a threat, but the whale populations are still recovering. While the sperm whale populations have recovered substantially, more than other large whale population, and are the most common large whale in the ocean, they are still listed as depleted under the Marine Mammal Protection Act and endangered under the Endangered Species Act.
Sperm whale lifespan
Sperm whales can live between 60 and 70 years.
Female sperm males have been found to reach sexual maturity at around 9 years of age, and are normally about 29 feet long (9 meters). Once they have reached this age and size, their growth slows and they start breeding. After a 14 to 16-month gestation, most birth a single calf every five to seven years. Most calves are a maximum length of 13 feet (close to 4 metres) when they are born.
Female sperm whales are physically mature when they reach 30 years old, at an average size of 35 feet long (11 metres) whereas male sperm whales grow substantially until their mid-30s and don't reach physical maturity until 50 years of age, at roughly 52 feet long (16 metres).
Most sperm whale females form bonds with other females in their families and create matriarchal groups of up to 12 females and their young. They stay with the same group in tropical waters for most of their lives.
Males on the other hand, leave their group before their early 20s and find other males around their size and age to create new social groups. As they get older, they migrate toward the poles and some sexually mature males return to tropical breeding grounds to mate.
According to research that studied mitochondrial DNA (genes that are passed to offspring from their mothers), all living sperm whales are derived from one single grandmother more than 80,000 years ago!
How much do sperm whales weigh?
While some adult sperm whales can be as big as 68 feet (20 metres), male sperm whales reach physical maturity at 52 feet (about 16 metres) and weigh up to 80 tons (179,200 pounds).
About three times smaller, female sperm whales grow to an average of 40 feet long.
How far do sperm whales migrate?
Sperm whales are found throughout the world's oceans, including in and near the ice in the Arctic and Antarctic. Where they live depends on their food source, and whether conditions are suitable for breeding and their habitat can change depending on the age and sex of the group.
Unlike some more predictable whale migrations, such as baleen whales, sperm whale migration is not well understood. Some sperm whale populations seem to have different migration patterns depending on their life history: adult males tend to make longer migrations into mild waters while female sperm whales and young sperm whales stay in more tropical waters all year long.
Sperm whale predators
Despite having few predators and a reduction in whaling practices, several countries throughout the world have granted sperm whales legal protection from various dangers, including:
Ocean Noise Pollution
Since sperm whales rely on sound to communicate and feed, noise from ships and other human causes can impact the lives of sperm whales. Sperm whales are known to make clicking sounds to navigate their surroundings, as well as whistles, groans, trills, chirps, squawks, yelps and pants to communicate with others that can be interrupted by ocean noise pollution.
Sperm whales can get caught up and entangled in fishing gear that can compromise their ability to hunt, swim, or breed and can cause injury and death.
Sperm whales have also been known to remove fish from fishing gear, this is known as depredation, and scientists believe this may be a learned, yet risky, behavior. Being near ships and fishing gear increases the whales chances of injury.
While more research needs to be done to understand the effects of oil spills and contaminants on sperm whales and their habitats, it is known that debris found in the water can be ingested by sperm whales, leading to injury, illness and death.
As ocean traffic increases, so too does the risk of collision for sperm whales.
Since sperm whales sleep and recover from deep dives near the surface of the water, they are more susceptible to being struck by large vessels.
Sperm whale sightings
Because sperm whales spend so much of their time hunting prey at deep sea levels, spotting a sperm whale near the coast is highly unlikely, instead sightings increase over deep water.
Consider Antarctic expeditions such as Crossing the Circle: Southern Expedition or Antarctic Express: Crossing the Circle, or the Spitsbergen Explorer: Wildlife Capital of the Arctic for your chance to see whales in their natural habitat.
Current estimates suggest there could be about 360,000 sperm whales in the oceans, so book your travel for your chance to see sperm whales today.