Whale facts

Whales are marine mammals that descended from land mammals that once roamed the planet millions of years ago. Throughout evolution, they adapted to a life out at sea. Now, they reign in the depths of the ocean far and wide. They are the largest animals to have ever existed, with the biggest hearts and brains of any animal. They communicate through beautiful and sophisticated songs, maintaining complex social structures. 

• Whales aren’t fish, they are mammals: they evolved from a common deer-like ancestor about 50 million years ago.
• Blue whales are the largest animals ever; they can grow beyond 30 metres long and weigh more than 150,000 kg. Their heart is the weight of a piano.
• Sperm whales have the largest brains of any animal.
• While scientists thought whales lived up to 90 years of age, new research suggests some whales live over 150 years.
• Beaked whales hold the record for the deepest mammalian dive recorded, plunging to a remarkable 3,000 metres.
• Some whale species have a ‘grandmother effect’, where older female whales that can no longer reproduce stay with their families for years to help younger generations.
• Humpback songs consist of repeated sequences of sounds organised into phrases and themes, often changing gradually over time within a population - kind of like evolving music. 

Around 50 million years ago, an ancestor of the even-toed ungulates (modern-day cows, pigs, camels, and deer) took an evolutionary U-turn and ventured back into the ocean and evolved into modern-day whales.¹

Scientists have used genetic analysis and fossils to pinpoint that a species of ancient, small deer known as Pakicetus was likely the first evolutionary stage the lineage of modern whales.² It had an amphibious lifestyle, living both on land and in water.

Over the course of millennia, these whale ancestors spent more and more time underwater.³ They evolved from four-legged land mammals to a powerful, slick, torpedo-shaped marine mammals instead. They traded their snouts for blowholes, grew the ability to hold their breath underwater for a longer time, got thick and water-resistant skin, lost most of their hair, and evolved their four limbs into powerful, flapping flukes. Their sense of  smell and taste was greatly reduced, their ears changes, and their metabolism and their immune systems adapted.⁴

Whales evolved over the last 10 million years during a transitional period where ancient and modern whales co-existed.⁵ By 5 million years ago, all ancient whales died out, and only modern whales remained. Whales are now most closely related to hippos, although they are not direct ancestors; they diverged from whales about 54 million years ago.⁶

Whales are split into two big groups that are thought to have diverged about 34 million years ago.⁷

These are Baleen whales, which include right whales and grey whales, and toothed whales, which include orcas, sperm whales, belugas, narwhals, and beaked whales, to name a few. The difference between them can be found in their names: toothed whales have sharp teeth they use to hunt prey, while baleen whales are filter feeders that eat plankton and ocean microorganisms by sucking them into their mouths and sieving them through baleen plates.⁸ Baleen plates are a comb like structure made out of keratin, the same material as your nails and hair.

Baleen whales also have two blowholes on top of their heads, while toothed whales only have one.⁹ Baleen whales tend to be much larger than toothed whales, sperm whales being the exception. Toothed whales are highly sociable and hunt using echolocation. Baleen whales tend to be more solitary, and they do not use echolocation to hunt.

There are 15 baleen whale species and 77 species of toothed whales, a classification that includes dolphins and porpoises.¹⁰

Whales are marine mammals that evolved from a common mammalian ancestor that lived on land. Over time, they evolved a variety of adaptations to thrive in the ocean: whales do everything in the water, including hunting, sleeping, eating, mating, and even giving birth in the water.¹¹

Fossil records suggest whales had legs up to 40 million years ago.¹² You can still see evidence of this in modern whales; they have vestigial limbs – unused bones in their tail that used to be back legs! Other indicators that whales are mammals include the fact that they breathe air, they are warm-blooded, they have hair, and they give birth to live young.

Like all mammals, whales breathe air. They do not have gills, and they cannot absorb oxygen from the water, so they have to come up and out of the water for air at regular intervals. They breathe through their blowhole - nostrils that have evolved to the top of the head, where air is easier to access.¹³ Baleen whales have two blowholes, and toothed whales have one.

Interestingly, whales are voluntary breathers: they need to flex their muscles to breathe on purpose, not like humans, who breathe without having to think about it, as they are involuntary breathers.¹⁴ While we only exchange up to 15% of the air in our lungs when we breathe, whales exchange about up to 90% of all the oxygen they have in their lungs with every breath.¹⁵

Since whales are mammals, they are warm-blooded. Their body maintains the same temperature our bodies do: somewhere around 36.6˚C and 37.2˚C.¹⁶ This can be a challenge, because water conducts heat away from the body 25 times faster than air. If you’ve ever swum in a cold ocean, think about how quickly you get cold!

Whales retain their body heat using a few adaptations. Being large helps whales reduce heat loss because a larger volume-to-surface area ratio means there is less surface area per unit of body mass through which heat can escape. This makes it easier to retain body heat in cold water, as heat loss occurs mainly through the surface.

While they may not have a furry coat to keep warm, whales do have a thick layer of blubber. Blubber is basically a fat coat, a layer of fat cells and proteins grouped tightly all around the whole body right under the skin.¹⁷ It serves as an insulating layer from the outside, and in some whales, it stores energy for when they need a boost of warmth. Whales also have a very efficient, specialised circulatory system made of a sophisticated labyrinth of arteries and veins to manage how heat is distributed throughout their body.¹⁸

Since whales are mammals, they still have hair. Of course, they’re not as furry as a llama or a bear. They lost almost all their hair during evolution to reduce drag underwater, but they still have some hairs.

All whales are born with sensory hairs on their jaws and heads.¹⁹ Many species shed those sensory hairs as they mature, but some species retain anywhere from 30 to 100 hair follicles, including fin, sei, right, and bowhead whales.²⁰ Humpback whales are the hairiest whales: the big lumps on their heads each contain one hair follicle. They use these to understand their surroundings better, including measuring plankton density in the water around them.²¹

Blue whales are a species of baleen whales. They get their name from their blue-grey colour that is clearly visible underwater.

They are found in all oceans except the Arctic Ocean, and they undertake lengthy migrations between winter feeding grounds and summer breeding ones. They eat humongous amounts of krill by taking large gulps of water and straining it through their baleen plates. Blue whales are known for being the largest animal on Earth, growing up to 30 metres in length and weighing as much as 90 metric tonnes.²² Blue whales are also the loudest animals on the planet, as their low frequency songs are as loud as a jet plane.²³ 

Humpback whales are baleen whales, like blue whales. They get their common name because of their dorsal hump, but their go their scientific name –Megaptera, meaning big-winged – because they have the longest fins of any whale species, measuring one-third of their body length.²⁴

Humpbacks can get as long as 15 metres and weigh over 36 metric tonnes. They are mostly grey-black, with streaks of white on their fins and their flukes. They’re found in all of the world’s oceans, but they also migrate far and wide with some swimming 8,000 kilometres every year - the longest migration of any mammal.²⁵ They are highly acrobatic, and love to jump out of the water and splash against the surface in acts called breaching. 

Grey whales are the only bottom-feeding species of baleen whale. They mostly live in coastal areas where the water is shallow, and feed by scooping huge mouthfuls of mud from the seafloor and straining it with their baleen plates.²⁶ This feeding style churns up the mud and creates a flow of nutrients in the water.

They used to inhabit the oceans across all of the Northern Hemisphere, but there are just two main populations now: one on the eastern side and one on the western side of the North Pacific.²⁷

The famous whale in the novel Moby Dick by Herman Melville is a sperm whale.²⁸ Sperm whales are the largest species of toothed whales, and they have the largest brain of any animal on the planet at 8,000 cubic centimetres of brain mass, compared to our 1300 cubic centimetres.²⁹ They are widely distributed across the oceans of the Earth, reaching as far up as the Arctic and as down to the Antarctic Circle. Sperm whales are deep divers who plunge as far as 3 kilometres beneath the surface, to gorge on their preferred meal: giant squid.

Their name comes from the word spermaceti, which is the waxy substance found inside their huge, box-shaped heads that takes up 40% of their body length.³⁰ The whale uses the spermaceti wax to enhance its echolocation abilities and sense their surroundings. Whalers in the 1800s hunted sperm whales for this substance, using it to fuel lamps and as a lubricant, and their populations rapidly plummeted during that time. The sperm whale is listed as vulnerable by the IUCN, but scientists think their populations could be recovering.³¹

Whales are found in all the world’s oceans, but some species have more restricted distributions than others. Humpback whales are found across the globe and migrate between warm and cold locations throughout the year.³² Killer whales are found all over the world, while Bryde's whales are mainly found in the warm waters of the tropics and they’re often dubbed the “tropical whales”.³³ Sperm whales have a huge distribution, even going are far as the edges of the Arctic.³⁴ 

Baleen whales mainly feed on tiny, tiny plankton and krill, but they also might eat small fish and crustaceans.³⁵ They take big mouthfuls of water and strain their meals through their baleen plates.

Blue whales feed almost exclusively on krill. They swim upwards towards their prey and take a huge gulp of krill on the way to the surface, their mouths stretched open wide.³⁶ Bowhead and right whales feed by skimming the surface of the water with their huge mouths open, eating floating zooplankton.³⁷ Grey whales feed by scooping huge mouthfuls of mud from the seafloor and straining it with their baleen plates.³⁸

Humpback whales also hunt for small schooling fish such as anchovies. (39) Interestingly, they sometimes trap their meals by swimming around in circles and releasing bubbles to make a water and air net.⁴⁰ The net closes in on the prey, making them clump together in an easily snackable bite. Scientists have also observed humpback whales make artificial ponds inside their mouths by opening their gape just at the surface of the water, trapping fish inside, and then clamping down on them.⁴¹

Toothed whales like sperm whales and killer whales have teeth designed to bite down on larger prey. They chase and hunt down their food, eating squid, fish, octopus, seals, and other marine mammals, gripping prey in their teeth and shaking it apart into smaller pieces.⁴²

There is a huge variety in the types of food and the amount of food that different whale species eat. The eating habits of baleen whales have been notoriously difficult to track because the ocean giants are elusive and hard to study. They are filter feeders, so they eat krill and plankton by taking large gulps of ocean water in their huge mouths and sieving them through their baleens.

In 2021, scientists published a study detailing the data they collected by tracking 321 baleen whales from different species and drones to measure krill concentrations.⁴³ They discovered that the tagged whales ate anywhere from 5 to 30 per cent of their body weight in krill each day. Blue whales were the most voracious, as one blue whale eats an average of 16 tonnes of krill every day: that’s the equivalent of 8,800 quarter pound burgers in one day, and about three times more than scientists had thought.⁴⁴

Research suggests whales do most of their stockpiling during summer: it likely takes whales just 90 to 120 days to ingest 83% of the calories it needs to survive for a year.⁴⁵

Toothed whales hunt their food and often eat larger fish and molluscs. Sperm whales, the biggest of the toothed whales, can consume about 3 per cent of their body weight per day.⁴⁶ The voracious killer whale, one of the ocean’s apex predators, can eat up to 170 kilograms of food out in the wild.⁴⁷

The myth of a whale swallowing a human is a popular one – from the biblical figure of Jonah to Pinocchio, humans have been fascinated by this possibility. In reality, a whale cannot eat a human. While they have huge mouths, most baleen whales have throats that are too narrow to swallow a human.⁴⁸ It’s possible that a very large, toothed whale, like a sperm whale could swallow a human – but they hunt in the deep ocean, far deeper than any human could swim.

That’s not to say that a human could accidently end up in a whale’s mouth. In 2024 a video circulated of a kayaker off the coast of Chile getting caught then spat out immediately.⁴⁹ Whales have no interest in eating us, accidentally catching a human in their mouths could lead to severe injuries.

Yes, whales do have predators, especially when they are young. Polar bears eat Arctic whale species such as belugas and narwhals, and smaller whales may sometimes fall prey to sharks and killer whales.⁵⁰ But since most whales are so gigantic, they do not have predators. Very rarely, a pod (group) of killer whales can attack even large humpback whales or blue whales.

The main risk for whales has always been humans. Historically, since the Stone Age, humans have hunted whales for meat, oil, blubber, cartilage, bones, and ambergris. During the Industrial Revolution, whaling became a successful commercial activity that grew rapidly, severely depleting whale populations.

In 1986, the International Whaling Commission banned commercial whaling all over the world. The commission made an exception for some Indigenous communities of the Arctic Circle in Alaska, Canada, and Greenland for cultural and nutritional needs.⁵¹ However, Norway, Iceland, and Japan do not agree with the moratorium, and they continue to hunt for whales, killing 40,000 large whales since the moratorium.⁵²

The largest animal on Earth, and the largest animal to have ever existed, is a whale, although size varies quite widely from species to species.⁵³

Blue whales hold the record for largest, reaching lengths of approximately 30 metres — that’s a third of a soccer field — and 150,000 kilograms in weight.⁵⁴ They also have the largest heart of any animal on the planet: their 200-kilogram heart weighs as much as a piano and pumps a whopping 60 gallons of blood with each heartbeat.⁵⁵ A growing body of researchers is trying to understand why it makes evolutionary sense to get so incredibly gigantic.⁵⁶

Fin whales can grow to 25 metres in length as the second largest species and they can weigh 36,000 kilograms.⁵⁷ Grey whales can grow to about half the size of blue whales, at 15 metres, weighing 40,000 kilograms.⁵⁸ Bowheads have the largest mouths of any whale, as their gape can measure five metres in length and four metres in height with huge, muscular tongues which weigh about 900kg.⁵⁹ Male right whales are the largest when it comes to genitalia, though: their penis measures more than 2 metres, and their testicles weigh more than 500 kilograms.⁶⁰

In 2023, scientists published a study describing how fossils from a desert in Peru indicated an ancient whale species from almost 40 million years ago that was so huge and heavy it could have been the heaviest animal to ever exist.⁶¹ Like a huge thick slug with small legs and arms, the Perucetus colossus, could have weighed between 85,000 and 340,000 kilograms. 

The lifespan of whales varies between species. Most tooth whales live between 20 and 60 years, and baleen whales generally live even longer than that.⁶²

Some species are incredibly long-lived. In 2024, scientists studying right whales calculated that they grow older than 100 years of age, and 10% of them may live past 130 years or up to 150.⁶³ This is twice longer than was previously thought. The bowhead whale lives the longest, sometimes up to 200.⁶⁴

It’s remarkable for an animal so humongous to grow so old. Because they have many more cells than smaller animals, and each of these cells has the potential to trigger a tumour. Technically, the more cells you have, the more likely you are to get cancer. But whales — like elephants — manage to grow very large without dying from cancer very often. In the scientific world, this is called Peto’s Paradox, and doctors are trying to hone in on what exactly protects whales from cancer in order to hopefully find medical applications for humans too.⁶⁵

Scientists know that sperm whales regularly dive to depths of up to a whopping 2,000 metres. But in 2014, scientists following eight tagged Cuvier’s beaked whales in California measured them diving as deep as 2,992 metres below the surface.⁶⁶ That’s eight times the height of the Empire State Building. Those same scientists recently analysed data from those trackers to discover that, on average, the beaked whales spend an hour diving that deep, while 5% of them spend more than an hour and a quarter.⁶⁷

Whales have special biological adaptations to allow them to dive so deep, including specialised chambered lungs that they can collapse.⁶⁸ Still, scientists have found gas bubbles in the bloodstreams of some stranded whales, suggesting they may suffer from the bends (the damaging formation of bubbles in blood) just like humans, if they ascend too quickly from their plunges.⁶⁹

Yes, most whales are migratory animals. Baleen whales have the longest migrations of any mammal. They travel from feeding areas in the summer to mating grounds in the winter, going up and down the planet’s oceans each year. Humpback whales swim more than 8,000 kilometres from Antarctica to tropical mating grounds, while grey whales travel more than 5,000 kilometres from feeding in Russia to breeding in California.⁷⁰

Scientists think that some pregnant whales migrate to warmer waters to give birth to protect their new-born calves from being attacked by killer whales, which prefer cold water. Warmer waters might be easier for child rearing in general since baby whales aren’t likely as adapted to thermoregulation as adult whales are. Some scientists have also recently suggested that migrating to warmer climates helps whales shed their skin, getting rid of harmful bacteria and undergoing the whale equivalent of a full body scrub.⁷¹

Not much is known about whale sleep… but scientists have spotted a couple of different types of sleeping patterns. Some whales sleep by going up to the surface and resting while they float — a behaviour scientists call logging because the whales look like floating logs.⁷² Other species rest vertically in groups just 15 metres below the water's surface: this too has a resemblance to trees, as the whales hanging in water create a mesmerizing, forest-like formation.⁷³

They’re never in deep slumber like humans, though, or they would drown. Instead, they do something called unihemispheric sleep, where only half of their brain sleeps while the other one is alert, checking for any danger, staying afloat, and telling the whale's body to remember to breathe.⁷⁴ Not much is known about how much whales sleep, but scientists estimate that sperm whales, for instance, spend only about 7% of their day sleeping in short 15-minute nap bursts.⁷⁵

Baleen whales have evolved to produce super low-frequency sounds which can travel far and wide — the sounds we think of as whale songs.⁷⁶ Some whales can emit infrasonic sounds and reach frequencies inaudible to humans - as low as 12.5 Hz. These whale songs are sophisticated and complex, and recent research suggests they have structural patterns similar to that of human language.⁷⁷

In fact, in 2021, researchers off the coast of Alaska initiated a conversation with a humpback whale called Twain by playing a recording of a humpback greeting call using an underwater speaker.⁷⁸ The whale responded, engaging in conversation for 20 minutes.

Toothed whales, on the other hand, use click-like sounds to communicate and to understand their surroundings.⁷⁹ Through echolocation, they emit ultra-fast clicks that bounce off objects in the surrounding area so the whales can detect where their prey is. For sperm whales, the clicks are arranged in patterns unique to their social groups.

Most baleen whales don’t tend to be particularly social, spending a great deal of their time solo - unless it's time to mate. Humpback whales are an exception, sometimes feeding in groups.⁸⁰

Several species of toothed whales are highly social animals with complex networks of family and non-family bonds.⁸¹ Some species are even thought to mourn their dead.⁸²

Beluga whales have complex social networks — small pods interconnected into bigger, intergenerational communities —while killer whales and sperm whales have matriarchal societies where several generations of related females stay together for their whole lives. (83) Young males leave when they reach sexual maturity to find a mate. While groups can have just a couple of members, others include up to 70 whales at the same time. Groups can be together for a matter of hours to a matter of days.

Sperm whales also have highly intricate, social lives. Hal Whitehead, a whale scientist from Dalhousie University, has been following sperm whales off the coast of the Galapagos for several years. These whales make uniquely patterned clicking sounds underwater to communicate, and each group has their own clicking pattern to differentiate themselves from other sperm whales. “They know these guys are my clan. These are another clan who we don't hang out with and that, to me, has been pretty fantastic,” says Whitehead. Clans can be made of 10,000 to 20,000 animals each.

Whales that live in matriarchal societies, where several generations of related females stay together for their whole lives, can have the equivalent of ‘grandmothers’. These are typically older females who enter menopause and can no longer reproduce: these grandmother whales teach younger whales everything from hunting and foraging strategies to unique language and cultural behaviours.

Studies suggest this has an evolutionary benefit, dubbed ‘the grandmother effect’. Data indicates grandmother whales improve the survival of the baby whales, likely by sharing knowledge about migration routes and best feeding grounds.⁸⁴

Matriarchal groups where females that can no longer reproduce maintain a high social standing is rare among animals, however it has evolved independently several times in whales.⁸⁵

Since the International Whaling Commission placed a ban on whale hunting in 1986, only a few countries still engage in whaling for cultural or commercial reasons. But humans pose risks to whales in other ways.

Whales can die due to accidental collisions with huge commercial vessels. An estimated 300,000 whales die every year because they are accidental bycatch by big commercial fisheries,caught in fishing nets and choked by fishing gear.⁸⁶ Chemical and plastic pollution in the ocean also affects whales, as does the copious amount of sound pollution our ships and military sonars produce. Studies show whales are highly sensitive to military underwater sonars because they impact their ability to echolocate, so much so that data shows that when disrupted by those sounds, whales abandon what they’re doing and flee, even if they’re feeding.⁸⁷ Mass whale strandings have increased since the introduction of military sonar.⁸⁸

It is not easy to calculate exactly how many whales are left in the world as they’re constantly moving, they live in the deep, and they often inhabit remote regions. But the data obtained so far shows that several species are vulnerable or on the brink of extinction.⁸⁹ Rice whales from the Gulf of Mexico, are on the brink of extinction with a population of only about 50 individuals, and there are just about 350 North Atlantic right whales left.⁹⁰

After the whaling moratorium, several whale populations that were highly coveted by hunters are showing signs of recovery including humpback and blue whales.