Facts about orcas (killer whales)
Orcas (also known as killer whales) are marine mammals. They belong to the sub-order of toothed whales (known as odontocetes) but are also the largest member of the dolphin family.
Orcas are incredibly popular as they are the most widely distributed of all whales and dolphins, found in every single ocean! They are very familiar with their black and white colouring but actually, depending on where they live, have very different appearances, behaviour, ways of communicating and diet! Find out some amazing facts below about the incredible orcas.
Ten facts about orcas (killer whales)
- Orcas are the largest member of the dolphin family.
- A male orca can be nearly 33 feet (10 meters) in length and weigh around 22,000 pounds (10,000kg).
- Orcas are highly intelligent and able to coordinate hunting tactics.
- Female orcas are thought to live to 80 years of age or more.
- The dorsal fin of a male orca is up to 6 feet (2 meters) tall.
- Orcas are extremely fast swimmers and have been recorded at speeds of up to 33.5 mph (54 kph).
- A wild orca pod can cover over 99 miles (160 kilometers) a day, foraging and socializing.
- They were give the name “killer whale” by ancient sailors who saw them preying on large whales.
- Orcas are still hunted in some countries, such as Greenland.
- Different kinds of orcas are called “ecotypes”. They hunt specific prey and live in different parts of the world.
Dolphins and whales are closely related. Orcas were given the name ‘killer whale’ by ancient sailors’ observations of groups of orcas hunting and preying on larger whale species. They called orcas asesina ballenas, or ‘whale killer’ – a term that was eventually flipped around to the easier ‘killer whale’. Their Latin name, Orcinus orca, also reflects this observation of orcas feeding on large whales. Orcinus translates to ‘of the kingdom of the dead,’ and orca refers to a kind of whale. We know that orcas are top predators, yes, but not the vicious ‘whale killers’ that the ancient mariners thought them to be. If you could give orcas another name, what would you call them?
What do orcas eat?
Looking at all populations, orcas are generalist eaters, consuming fish, seals and sea lions, dolphins and porpoises, sharks and rays, large whales, cephalopods (octopods and squids), seabirds and more. However, some orcas specialise on specific prey, and it turns out orcas are picky eaters! Once they’ve learned what their family eats, they aren’t likely to switch diets.
Orcas sleep in a very different way to humans. We have a breathing reflex and when we sleep or become unconscious, we continue to breath automatically. Orcas cannot sleep in this way, they have to remain conscious, even when they are sleeping! This is because their breathing is not automatic – they have to actively decide when to breath, and so they must be conscious even when sleeping. If like us, orcas went into a deep unconscious sleep, they would stop breathing and suffocate or drown.
To get around this, orcas only allow one half of their brains to sleep at a time; the other half stays alert enabling them to continue breathing whilst looking out for dangers in the environment. They only close one eye when they sleep; the left eye will be closed when the right half of the brain sleeps, and vice versa. This type of sleep is known as unihemispheric sleep as only one brain hemisphere sleeps at a time. Orcas periodically alternate which side is sleeping so that they can get the rest they need without ever losing consciousness. When sleeping, orcas swim very slowly and steadily, close to the surface.
Orcas: Facts about killer whales
Orcas, or killer whales, are deadly and beautiful apex predators that lurk in every ocean.
An orca looking out of the water at sunset, off Kaldfjorden in Norway. (Image credit: Michael Weberberger via Getty Images)
- Orca attacks on humans
- Orca pods
- Types of orca
- Conservation status
- Famous orcas
- Additional resources
Orcas (Orcinus orca) are often called killer whales, even though they almost never attack humans. In fact, the killer whale name was originally “whale killer,” as ancient sailors saw them hunting in groups to take down large whales, according to Whale and Dolphin Conservation (WDC) (opens in new tab) .
Today, orcas are recognized as among the most widely distributed mammals on the planet, occupying every ocean. They are incredibly social, diverse and ferocious marine predators with a diet ranging from penguins to great white sharks.
How big is an orca?
Orcas are the largest members of the dolphin family. Males are bigger than females, but they vary in size and weight, depending on the type of orca. The largest orca ever recorded was a staggering 32 feet (9.8 meters) long and weighed 22,000 lbs. (10,000 kilograms), according to SeaWorld (opens in new tab) . That’s longer and heavier than most motorhomes.
Orcas are known for their long dorsal fin (the fin on the animal’s back) and black-and-white coloring. The black-and-white coloring helps to camouflage them by obscuring their outline in the water. Just behind the dorsal fin is a patch of gray called a “saddle” — because it looks like a riding saddle.
An orca’s body is cylindrical and tapers at each end to form a hydrodynamic shape. This shape, along with the orca’s large size and strength, makes it among the fastest marine mammals, able to reach speeds in excess of 30 knots (about 34 mph, or 56 km/h). Orcas have massive teeth, which can grow up to 4 inches (10 centimeters) long, according to National Geographic (opens in new tab) .
What do orcas eat?
Orcas are apex predators, at the top of the food chain. No animals hunt orcas (except for humans). Killer whales feed on many different types of prey, including fish, seals, sea birds and squid. They can also take down whales larger than themselves, such as minke whales, and they are the only animal known to predate on great white sharks, according to The Natural History Museum in London (opens in new tab) . Killer whales have even been reported to kill swimming deer and moose, according to a chapter on orcas in the book “Primates and Cetaceans (opens in new tab) ,” (Sringer, 2014).
Orcas use many different techniques to catch prey. Sometimes they beach themselves to catch seals on land, jumping from the water onto land. Orcas will also work together to catch larger prey or groups of prey, such as schools of fish, according to the International Union for Conservation of Nature’s (IUCN) Red List (opens in new tab) . They can use echolocation to identify their prey by creating sounds, or sound waves, that travel through the water. These waves echo off objects, including prey, which the orcas can use to locate them, according to SeaWorld (opens in new tab) .
Orca attacks on humans
There is no record of an orca ever killing a human in the wild. This is because humans are not part of their natural diet. Occasionally, an orca may mistake a human for something they do eat, such as a seal. In 2017, an orca was caught on camera charging at a surfer during the Lofoten Masters surfing competition in Norway. The orca seemed to pull out of the attack just before making contact. The Norwegian Orca Survey (opens in new tab) said in a Facebook post that the orca likely realized the surfer was not a seal at the very last second.
In 2005, a 12-year-old boy was “bumped” by a killer whale near Ketchikan, Alaska, in what may have been an aborted attack — similar to the surfer in Norway — or simply curiosity on behalf of the orca, according to the Associated Press, via The Seattle Times. The Associated Press reported that a surfer was bitten in California in the early 1970s, which is the only relatively well-documented case of a wild orca actually biting a human. Orcas in captivity, however, have attacked and killed people.
Although wild killer whales do not intentionally harm people, they have attacked boats. There were many reports beginning in the summer of 2020 of orcas ramming into and causing damage to sailing boats off the coast of Spain and Portugal, according to BBC News (opens in new tab) . Three juvenile male orcas were involved in most of the attacks, and marine biologists investigating the incidents believe that the young males were playing with the boats by targeting the rudders and pushing the boats around.
Life in the pod
An adult killer whale and calf surfacing off the Cumberland Peninsula in Canada. (Image credit: Michael Nolan via Getty Images)
Orcas are very social creatures and live in family groups called pods, which have up to 50 members, according to the University of Michigan’s Animal Diversity Web (ADW) (opens in new tab) . These pods are made up of related mothers and their descendants, known as matrilines. A male orca will stay with its mother for life, while daughters may spend time away after having calves of their own, according to the wildlife charity Whale and Dolphin Conservation (WDC (opens in new tab) ). Pods often have their own distinctive calls, or dialects, to communicate, but they will associate with other pods and can come together to form even larger, temporary groups.
Size: Up to 32 feet (9.8 m) long
Life span: Up to 100 years
Conservation status: Data deficient
A female killer whale will give birth to one offspring at a time every three to 10 years. The gestation period usually lasts for around 17 months according to SeaWorld (opens in new tab) . Orcas work together to take care of the young, and other females in the pod will often help with the rearing.
Female killer whales have an average life span of 50 years, but some individuals are estimated to have lived up to 100 years. Males live shorter lives, with an average life span of 29 years and a maximum life span of 60 years, according to the Center for Whale Research (opens in new tab) in Washington state.
Where do orcas live?
Killer whales are the most widely distributed mammals, other than humans and possibly brown rats, according to SeaWorld (opens in new tab) . They live in every ocean around the world and have adapted to different climates, from the warm waters near the equator to the icy waters of the North and South Pole regions.
Orcas have been known to travel long distances. For example, one study found that a group of orcas traveled from the waters off of Alaska to those near central California, according to IUCN — a distance of more than 1,200 miles (1,900 km).
Are there different types of orca?
All orcas are currently listed under one species, Orcinus orca. However, there are recognizable differences between populations, and biologists have identified several distinct forms, known as ecotypes, which may actually be different species or subspecies, according to the National Oceanic and Atmospheric Administration (NOAA) (opens in new tab) .
Killer whale ecotypes can vary in size, diet and behavior. There are currently 10 described ecotypes: five in the Northern Hemisphere and five in the Southern Hemisphere, according to WDC (opens in new tab) . In the North Pacific, scientists have identified resident orcas, which tend to have small ranges — hence the name — and specialize in catching fish. Bigg’s killer whales, or transient orcas, can also be found in the North Pacific. These orcas travel great distances and hunt mammals such as seals and whale calves. Offshore orcas can also be found in this region. They live far from coastlines and have been seen eating fish and sharks, but relatively little is known about them.
The Northern Hemisphere is also home to North Atlantic Type 1 and Type 2 killer whales. Type 1 orcas are generalist eaters and have been observed eating fish and seals around European countries, including Norway and Scotland. Type 2 orcas are rarer and mainly eat other whales and dolphins.
In the Southern Hemisphere, there are Type A, Type B (large), Type B (small), Type C and Type D killer whales.
—Type A orcas travel in and out of Antarctic waters, following the migration of their main prey, minke whales.
—Type B (large) animals are also called pack ice orcas, because they hunt seals in Antarctic pack ice.
—Type B (small) killer whales, also called Gerlache orcas, have been seen eating penguins, but their complete diet is unknown.
—The same is true for Type C and Type D orcas, though both of these have been observed eating fish.
—Type C, or Ross Sea orcas, are the smallest ecotype and are usually found in eastern Antarctica.
—Type D, or subantarctic orcas, are very rare, and there is still much to learn about them.
Are orcas endangered?
The orca is currently listed as “Data Deficient” by the IUCN (opens in new tab) , which means its conservation status is unknown. Scientists didn’t have sufficient data when it was last assessed in 2017 due to the uncertainty regarding its taxonomic classification — whether orcas should be split into different subspecies or species. The IUCN noted that as a single species, the killer whale is abundant and widely distributed. However, they still face threats from human activities and some regional populations, such as the orcas dependent on bluefin tuna in the Strait of Gibraltar, have declined significantly.
Human civilizations around the world kill orcas directly and indirectly. They are still hunted for food in small numbers, or as a means to control their population, in Greenland, Japan, Indonesia and the Caribbean, according to the IUCN. Contaminants in the ocean and seas, such as chemicals and oil, pose a threat to orcas along with disturbance by boats, overfishing and other disruptions to their food supply and climate change, according to IUCN.
Killer whales are protected in the U.S under the Marine Mammal Protection Act (MMPA). Southern resident killer whales are also listed under the Endangered Species Act as they are at particular risk of extinction, due to threats like noise from boat traffic and a decline in the salmon population — their preferred food. A subpopulation of transient killer whales (AT1) is also listed as “depleted” under the MMPA. The population consists of just seven individuals, following a dramatic decline in the wake of the 1989 Exxon Valdez oil spill in Prince William Sound, Alaska, according to NOAA (opens in new tab) .
Keiko the orca from Free Willy at the Oregon Coast Aquarium. (Image credit: Kevin Schafer via Getty Images)
A SeaWorld orca named Tilikum was the focus of the popular 2013 documentary “Blackfish,” which took a critical look at killer whales in captivity. Tilikum was involved in three human deaths, including that of SeaWorld trainer Dawn Brancheau in 2010. The documentary created a public backlash against SeaWorld, and in 2016 the marine park chain announced that it was ending its killer whale breeding program, Live Science previously reported. Tilikum died of a bacterial infection at SeaWorld in 2017 at the age of 36.
Another famous captive orca was Keiko, who played Willy in the 1993 film “Free Willy.” Keiko lived in a marine park in Mexico, but after the film’s release, an international campaign was launched to return him to the wild Icelandic waters from which he was captured when he was about 2 years old. Keiko was trained to catch wild fish and was released off the coast of Iceland in 2002. He swam to the coast of Norway but died of pneumonia, 18 months after his release, at the age of 27, according to BBC News (opens in new tab) .
An all-white orca named “Iceberg” was spotted in waters around the Commander Islands, off the east coast of Russia, in 2010, Live Science previously reported. The ghostly white dorsal fin of this mature male stood out dramatically from those of its black-and-white podmates. Researchers at the Far East Russia Orca Project (FEROP), who discovered Iceberg, found more white orcas in Russian waters, and suggested that most are albino, although it is not known for certain, according to WDC (opens in new tab) . Albino orcas could indicate inbreeding in the population.
Learn more about how endangered killer whales are on the ICUN redlist (opens in new tab) , get an overview of the Orcinus orca from NOAA Fisheries (opens in new tab) , and see how you can help save this beautiful species from extinction at the Center for Whale Research.
- John K B Ford “You Are What You Eat: Foraging Specializations and Their Influence on the Social Organization and Behavior of Killer Whales (opens in new tab) “
- Eve Jourdain, Fernando Ugarte, Gísli A. Víkingsson, Filipa I. P. Samarra, Steven H. Ferguson, Jack Lawson, Dag Vongraven, Geneviève Desportes North Atlantic killer whale Orcinus orca populations: a review of current knowledge and threats to conservation (opens in new tab)
- Heather M. Hill, Sara Guarino, Sarah Dietrich, & Judy St. Leger An Inventory of Peer-reviewed Articles on Killer Whales (Orcinus orca) with a Comparison to Bottlenose Dolphins (Tursiops truncatus) (opens in new tab)
- ‘Facts about Orcas’, Whale and Dolphin Conservation
- “Primates and Cetaceans (opens in new tab) ” , Ed. Juichi YamagiwaLeszek Karczmarski, Springer (opens in new tab)
- ‘Species Directory: Killer Whale’, International Union for the Conservation of Nature
- ‘About Orcas’ Center for Whale Research (opens in new tab)
Alina Bradford is a contributing writer for Live Science. Over the past 16 years, Alina has covered everything from Ebola to androids while writing health, science and tech articles for major publications. She has multiple health, safety and lifesaving certifications from Oklahoma State University. Alina’s goal in life is to try as many experiences as possible. To date, she has been a volunteer firefighter, a dispatcher, substitute teacher, artist, janitor, children’s book author, pizza maker, event coordinator and much more.
What do killer whales eat?
Killer whales (also called orcas) are apex predators, meaning they are at the top of their food chain. They feed on fish and squid like other odontocetes (toothed whales) do, but will also target seals, sea birds and even whale species far bigger than themselves. Killer whales are also the only known predators of great white sharks.
Killer whales are the largest dolphin species. They are highly social and spend most of their lives swimming in large pods of family members. Hunting techniques are passed down through generations, so their diets depend on the region they inhabit and the pod’s approach to hunting.
These highly intelligent cetaceans have been documented creating large waves to wash seals off ice floes, and even intentionally beaching themselves to catch prey on the shore.
Diet & Eating Habits
Killer whales are top-level predators in the ocean. Killer whales are the largest predator of warm-blooded animals alive today.
Globally, killer whales appear to have an extremely diverse diet. Yet, individual ecotypes or populations are often extremely specialized. In many parts of the world, killer whales prey on fishes or marine mammals, but not both.
Worldwide, killer whales have been observed preying on more than 140 species of animals, including many species of bony fish, sharks and rays, and 50 different species of marine mammals.
Killer whales have also been reported to eat many other types of animals including leatherback sea turtles, dugongs, moose, and penguins and other seabirds.
Antarctic small type B killer whales have been observed hunting penguins like these Adélies.
Antarctic type A killer whales have been observed hunting southern elephant seals.
Each killer whale ecotype has a fairly specific diet.
- The five forms of Antarctic killer whales differ in their diet:
- Type A whales eat mostly Antarctic minke whales and have also been observed hunting southern elephant seals.
Minke whales are hunted by the North Atlantic type 2 killer whales in the northern hemisphere
and by the Antarctic type A and large type B ecotypes in the southern hemisphere.
- Large type B whales eat mainly seals, especially Weddell seals, and also hunt minke whales.
- Small type B killer whales have been observed hunting penguins and are believed to mainly eat fishes.
- Type C killer whales mostly eat Antarctic toothfish (Dissostichus mawsoni).
- Little is known about the diet of type D killer whales, however, they have been observed preying on Patagonian toothfish (Dissostichus eleginoides) caught on longlines.
- The feeding habits of resident and transient whales of the eastern North Pacific Ocean differ.
- Resident whales spend about 60% to 65% of daylight hours foraging for fishes. Salmon make up 96% of their diet; Chinook salmon (Oncorhynchus tshawytscha) is the preferred species. Their diet is highly specialized and this dependence may be a limiting factor for this population. To a much lesser degree, residents are also known to eat one species of squid (Gonatopsis borealis) and 22 other species of fish including rockfish (Sebastesspp.), Pacific halibut (Hippoglossus stenolepis) and Pacific herring (Clupea pallasi). There is no evidence of resident killer whales eating marine mammals.
The eastern North Pacific resident killer whales prefer Chinook salmon.
- Transient whales spend about 90% of daylight hours foraging. They primarily eat marine mammals including seals, sea lions, walruses, baleen whales, other toothed whales, and occasionally sea otters.
The transient ecotype in the eastern North Pacific hunt marine mammals including sea otters.
- Researchers theorize that the divergent, specialized feeding habits of resident and transient killer whales help prevent these two groups of whales from competing with each other for food.
- Such extremely different feeding habits, which is not known to occur in any other sympatric mammal species, has also resulted in significant differences in vocalizations, echolocation, group size and behavior between the two ecotypes.
- The diet of offshore killer whales in the northeastern Pacific include fishes such as salmon (Oncorhynchus spp.), sculpin (Cottus spp.), Pacific halibut (Hippoglossus stenolepis), and Pacific sleeper sharks (Somniosus pacificus).
- In the North Atlantic, the type 1 killer whales consume a varied diet that includes seals and small, schooling fishes such as herring and mackerel. Type 2 killer whales specialize in cetacean prey including dolphins, porpoises, and baleen whales such as minke whales.
- Although rarely seen, killer whales in Hawaiian waters seem to have a more varied diet including humpback whales, dolphins, octopuses and squids.
In the North Atlantic, type 1 killer whales hunt schooling fishes such as these herring.
The diet of killer whales in Hawaiian waters includes dolphins..
At SeaWorld parks, adult killer whales eat approximately 1% to 3.5% of their body weight in food per day.
Growing calves eat more — as much as 10% of body weight during growth periods.
- At zoological parks, calves begin to take a few fish at about two to three months.
- A killer whale’s lower teeth emerge at about 11 weeks.
- By the age of one year, calves at SeaWorld eat 23 to 27 kg (50 to 60 lbs.) of herring, smelt, and squid per day.
Killer whales don’t chew their food. They swallow their food whole, or they may tear or shred it.
Methods of Collecting Food
Killer whales often hunt cooperatively in pods for food.
- Salmon-eating resident killer whales in the North Pacific often pursue prey singularly or in small groups. After a successful kill they regularly (75% of the time) share their fish, usually family members and particularly offspring.
- At times killer whales work together to encircle and herd small prey before attacking. The comparatively large pod size of resident whales is an advantage when herding a school of fish.
- Researchers observed Norwegian killer whales hunting cooperatively using a “carousel-feeding” technique. They cooperatively herded small fishes into a tight ball close to the surface. Then the whales stunned the fishes with their tail flukes and ate the stunned fish.
- To hunt a large baleen whale, a pod of killer whales may attack the whale from several angles. One attack was witnessed by SeaWorld researchers. About 30 killer whales attacked an 18.2 m (60 ft.) blue whale. Two killer whales stayed ahead and two brought up the rear while the others surrounded the blue whale from the sides and underneath in an apparent effort to prevent escape. Some leaped onto its back. The whales took turns biting flesh and blubber from their prey. After five hours the pod broke off the attack.
- Around New Zealand a group of seven killer whales were observed hunting a shortfin mako shark (Isurus oxyrhinchus). As the shark attempted to retreat, it was bitten and held by its tail and then around its girth and head until consumed. Another group of killer whales was filmed attacking a blue shark (Prionace glauca) by striking it hard at the surface of the water with their tail flukes.
- Transient pods are known to “sneak attack” marine mammals. These small groups most often hit quietly or silently. Other observed transient hunting techniques include driving and trapping groups of Pacific white-sided dolphins in confined bays and ramming sea lions with their heads or stunning them with tail fluke swats before taking the animal underwater and drowning it.
- In the Antarctic, individual killer whales slide out onto ice floes to hunt penguins. Similarly, killer whales sometimes slide up onto sand bars or beaches to hunt pinnipeds such as juvenile elephant seals.
- Killer whales sometimes hit ice floes from below to knock penguins and pinnipeds into the water. When an ice floe is too big to be overturned, Antarctic type B killer whales will swiftly swim side-by-side at the ice floe, diving below the floe at the last second, to create a wave large enough to wash a hauled out seal into the water.
- Sometimes killer whales feed in connection with fisheries operations, eating fishes that slip from the nets and bycatch (nontarget fish caught during a fishing operation) discarded by fishermen. In some areas, killer whales congregate near longline boats and feed on the hooked fish.
To hunt a large baleen whale, a pod of killer whales may attack the whale from several angles.
Prey such as these sea lions, may not be safe from killer whales even on land.
What Eats Killer Whales?
As apex predators, killer whales have no known natural predators. Their lone threat from other animals has been from humans, who reduced their populations dramatically across the 20th century. In fact, killer whales are such fearsome predators that researchers from the Monterey Bay Aquarium discovered that when they entered an area great white sharks would flee! The research found that when killer whales arrived at a marine sanctuary near San Franciso, great whites would leave for an entire season.
Killer whales have not only been observed hunting great white sharks but can even hunt the world’s largest animal, the blue whale. In March 2021, a whale-watching tour of the coast of Australia discovered a massive pod of orcas hunting a blue whale that was estimated to be more than 50 feet in length.
Like all animals, killer whales can face threats when juveniles. However, since killer whales live in pods, even the youngest killer whales have protection from would-be predators.
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