Orcas, or killer whales, are some of the most majestic creatures in the ocean. They are known for their intelligence and playful nature. But don’t be fooled by that cute appearance, killer whales are fearsome and powerful predators of the food chain. In this article, we will explore some of the fascinating facts about orcas which will help us to understand them better.
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Genus: Orcinus
Family: Delphinidae
1. Orcas aren’t whales
Orcas are also known as killer whales. They are one of the enormous species of the sea. However, in contrast with their names, killer whales are not whales. These creatures are actually oceanic dolphins that belong to the Delphinidae family. Dolphins and whales have a close relationship.
The misconception was likely to be formed when ancient sailors witnessed groups of orcas attacking and feeding on bigger whales. From that moment, they are called orcas asesina ballenas, or ‘whale killer’. This phrase was later flipped to ‘killer whale’ that we know today.
In Latin, their name is Orcinus orca. Orcinus means “of the kingdom of the dead,” and the orca is a type of whale.
In recent years, orcas have taken center stage in popular culture due to famous documentaries and other media outlets. This species has long been an inspiration for films and movies. From the classic Free Willy (played by Keiko orca) to Jaws 3 (Kotar orca played Shamu) to the more recent Blackfish, moviegoers have seen a variety of stories about killer whales throughout the years.
2. They have a size of a bus
The killer whale is the biggest dolphin and one of the most deadly predators on the planet. You can easily recognize them by their black coloration along with white patches around the eyes and a white abdomen.
Its appearance is extremely advantageous for an orca – a predator that has a size of 8 meters in length and weighs 6 tons. The patterns help the orcas to blend in with their environment. It distorts their look and makes them more difficult to spot in the water.
However, these killer whales are easy to identify while swimming near the surface due to their tall dorsal fins. Females have shorter dorsal fins than that of males. The male’s dorsal fins can reach two meters in length, making them taller than most humans.
Adult orcas are as big as a school bus which is about 19 to 26 feet (5.8 – 8 m) in length. Their average weight is about six tons. The biggest orca in the world is a male with 32 feet (9.7m) and 22,000 pounds (9.9 tons).
Adult killer whales are, on average, about as long as (long) and they can weigh up to
3. They are widespread around the world
Killer whales are the worldwide animals, after humans. You can find these species in every ocean on the planet. They can be found from the Arctic to the Antarctic, from the icy oceans of the north and south to the warm waters of the equator, in the Arabian Sea, and in Japan’s coastal waters.
Not only that, killer whales also live in freshwater rivers. An orca had been known to swan 100 miles up the Columbia River in search of fish.
They have an extraordinarily broad range and irregular activities. This makes determining their precise global population challenging. It is estimated that there are more than 50,000 orcas in the world. However, some orca populations are listed as endangered.
You can see orcas in the wild in some locations:
- Alaska (USA): June – September
- San Juan Island (USA): April to October
- Antarctica: February-March
- Norway: November-early February
- Vancouver Island (Canada): May to October and July and August
- Bremer Bay (Australia): late January-early April
4. They are social animals
Killer whales are highly sociable creatures that live in groups which are called pods. The social systems of the pod are so complex that they can only be observed in higher animals such as elephants and humans.
Their pods are led by the oldest female killer whale – matriarch. She will decide where and when to eat for the group. Until the young reach adulthood, they will stay by their mothers’ side. It’s common to see a pod with four generations. In a pod, these creatures can whales may compete for dominance by scraping one another with their teeth, biting, or headbutting.
Adult pod members pass to the next generations their culture, critical skills in life (where and how to catch prey, what to consume and what should ignore), and the language of a group. This is what they call “cultural transmission.” Each orca family (pod) will have its own different vocal sounds and calls – the distinct ‘accent’ of a pod.
The members in a pod might vary significantly. Resident pods can range in size from 5 to 50 killer whales. Transient pods, on the other hand, normally include 7 individuals or less, and occasionally there’s only one full grown male.
Multiple pods will create a clan and many clans will form communities. These communities are so varied that they may not speak the same language.
5. They have big brains
Killer whales have the second largest brain of all animals. 3,600 to 7,260 kg (8,000 to 16,000 pounds) is the average weight of a killer whale. And its brain takes around 7 kg (15 pounds) of that number.
To estimate the intelligence of an animal, some scientists use the ratio of brain weight to body weight (Encephalization level – EL). According to that metric, the killer whale’s brain is 2.5 times larger than that of other species.
Its El ratio is comparable to that of a chimp but far lower than that of several cousins, such as bottlenose dolphins with the EL of 5.3. The EL for humans is 7.4.
In a 2001 study based on a mirror test, people studied the orca’s behavior in front of a mirror. They then stated that it appeared to “possess the cognitive ability necessary for self-recognition.”
Orcas’ intellect is believed to greatly exceed their brain capacity due to their excellent social, language, and infrasound abilities.
6. They are emotional
Spindle cells in our brains are thought to be in charge of processing complicated emotions like love, sympathy, and possibly sorrow. These cells are also found in great apes and killer whales.
In 2018, Tahlequah, a southern resident killer whale near British Columbia, carried her dead calf’s body for 17 days. The calf died soon after birth, and Tahlequah appeared reluctant to abandon her in the sea. Scientists believed it was a sign of grief. They also thought that the other members of the pod show their mourning ritual by helping the mother to push away her dead offspring.
7. They speak different languages
Each orca pod develops its own communication code. They employ various noises, like whistles, calls, and clicks, to create a distinct vocal language that is consistent with time. Only members of the pod can understand and identify the language, even from a distance.
Mothers transmit their own vocal language to their children. Scientists have recorded up to 17 distinct calls per pod, with a variety of modulations.
Language is a way to differentiate individual pods from one another. Although the pods use the same language, each has its own “dialect.” This is similar to English speakers who will have different accents, such as accents from the Southern, accents from Midwestern, and New England.
You can imagine that pods are like provinces of a country and clans are similar to nations. That’s why clans “speak” in wholly separate languages, like Russian, Vietnamese, English, or Spanish.
8. They’re the apex predator of the seas
Orcas are one of the most terrifying and deadly hunters of the ocean. While on the hunt, they employ very complex strategies, specific to each target.
On the food chain, they’re the apex predators, meaning they have no natural predators, except for humans. These giant dolphins are carnivores and eat a wide variety of foods. Their diets can include fish, cephalopods (like octopods and squids), other dolphins, sea lions, penguins, rays, sharks, seabirds, seals, and even whales (like humpback, gray, and blue whales).
Some pods will have their own favorite prey. Transient pods like marine mammals, whereas resident pods prefer fish. They are unlikely to switch their diets.
Killer whales usually hunt in pods of 40 members. With their intellect and sociability, different orca pods use various innovative methods to hunt different food from different locales. Their hunting strategies can be compared to wolf pack behavior.
– With seals: To hunt seals, they create a big wave on the icebergs where the seals are perched. The crashing wall of water will push the prey into the water, where they are simpler to capture.
– With fish: Orcas crowd schools of fish into a small ball near the surface by using a combo of air bubbles and belly flashes. They then use their tail to hit the ball to dazzle the fish and eat them all.
– With sharks
The killer whales use their wide tails to drive the shark to the top of the surface, creating a fluid vortex. They make a tiny spin and raise their tail into the air, crashing down on the head of the shark. The orcas then turn the shark over, making it immobile. And all they have to do is to eat the shark.
– With sea lions, elephant seals
With onshore prey like those, killer whales use their beaching techniques. They jump out of the water onto the shore, snare the prey, and then go back to the water by flapping and hopping their bodies. Orcas can also use this technique to frighten their prey into the water, where their family members are waiting.
– With larger whales
If their target is bigger than them, they will attack the young or weak one. They alternate smashing, biting, and dragging the whale’s pectoral fins
Then they leap from the water onto the back of the whale to cover its blowhole. Without enough oxygen for the several-hour chase, the whale is exhausted and drowns.
Killer whale teeth are powerful and sharp enough to cut the prey’s flesh at once. Without molars, orcas’ teeth are designed to grip, kill, and tear the prey into tiny pieces.
9. Reproduction
Killer whales are polygamous animals, with numerous mates in a single breeding season.
Based on the ecotype, males become sexually mature at roughly 13 years old. They can’t mate until they’re big and strong enough to compete with other males. To avoid inbreeding, males will depart their pods when mating.
Females, on the other hand, are sooner, around the age of 10. Their dorsal fin begins to become bigger and straighter between ages 12 and 15, indicating the start of sexual maturity. However, they do not normally mate until they are at least 20 years old. Females can get ovulated many times a year.
Many species are capable of reproducing until they die. However, some animals, such as orcas and humans, are exceptions. They reach menopause at the age of 40 and survive for decades after that.
After mating, the females will go through a gestation period that lasts roughly 15 to 18 months. They typically give birth to only a calf every 5 to 10 years, depending on the region. There are, however, certain exceptions. A female had a new calf only 19 months after her last offspring passed away a few years ago.
The newborn calves have a size of 2.4 meters in length and weights about 180 kilograms (396 lbs). The young orcas have a yellow tone in their skin that fades to white as they develop. But this tone can persist in some adults.
For roughly 18 months, the calf is fed with the mother’s milk. Every member of the pod is responsible for raising the young. The calf will wean when it’s 1 year old, the weaning process will last for a year.
Killer whale mothers, like other mammal moms, guard their young against predators and remain with them till they are able to defend themselves. During this time, the young learn to hunt and protect themselves.
In most situations, the relationship between the calf and its mother will ultimately diminish, and the young killer whale will have its own way. However, in some certain pods, the juvenile may spend its whole life with its original pod.
In the wild, the life expectancy of orcas is around 50 years for females and 30 years for males. Their lifespan, however, can be longer than those. Granny – a local resident female killer whale – lived till the age of 100. She is the leader of J-Pod and died in late 2016.
10. Orcas are unable to smell
Killer whales lack an olfactory system, meaning they are unlikely to smell. This happens the same to dolphins and most toothed whales.
While this may appear to be a disadvantage, it is not. While sharks depend on their sense of smell to locate prey, killer whales utilize echolocation.
The animals communicate and hunt by echo sounding to create sounds that travel underwater until they hit objects. The sounds then rebound, letting orcas know the presence of objects or creatures in their surroundings, their positions, sizes, and shapes.
11. They sleep with one eye open
Orcas don’t sleep like us! They would stop breathing and die or drown if they fall into unconscious sleep.
To avoid this, they only sleep with one brain. The other one remains alert, allowing them to keep breathing while keeping an eye open for potential threats in the surroundings. They close their right eyes when the left half of the brain sleeps. And conversely, the left eye closes when the right side of the brain sleeps. This is called unihemispheric sleep.
Killer whales switch which side sleeps on a regular basis so that they can obtain enough rest without losing awareness. These dolphins sleep by swimming slowly and steadily near the surface.
12. They belong to the nature
Orcas are extremely intelligent, sociable mammals. That’s why they’re usually illegally caught and used in marine parks for entertainment. However, it has become obvious that killer whales cannot live in captivity.
These animals are meant to swim 40 miles every day to look for food and to exercise. They dive 100 to 500 feet multiple times per day. No matter where they were born, they all have an intrinsic desire to swim long and dive deep.
Enclosures in captivity can’t provide killer whales with that kind of environment. This causes them bored and depressed, leading them to develop repeated activities like shaking, self-mutilation, or swinging.
As mentioned above, killer whales in nature live in close-knit family groupings that share a complex, distinctive culture. Orcas in captivity live in artificial pods and they are frequently relocated between institutions, disrupting their social bonds.
The documentary film Blackfish, released in 2013, revealed the psychological toll of confinement via the narrative of Tilikum, a wild-caught orca. This killer whale killed 2 trainers at SeaWorld Orlando. Conversely, in the wild, they do not attack humans and there are no fatalities reported.
Retired SeaWorld trainers and marine mammal specialists testified in the film, claiming that Tilikum’s stress was directly responsible for his aggressiveness toward humans.
There are more and more orcas dying at these marine parks at an alarming rate. At least 44 orcas died at SeaWorld. You can see the fate of killer whales in captivity here.
13. There’re 2 main types of orcas
According to scientists, there are numerous types of orcas (called ecotypes). They exist in various places of the world and seek specialized prey.
a. Northern Hemisphere
Resident orcas
- Habitat: Live on both sides of the North Pacific
- Diet: Mainly fish. The Southern and Northern communities almost entirely consume salmon, whereas the pods in Alaska consume a variety of fish species, such as halibut, salmon, cod, and mackerel.
- Community: Live in large communities, the young spend their entire lives with their mother.
Bigg’s orcas (transient orcas)
- Habitat: From Southern California up to the Arctic Circle
- Diet: Mammals, including harbor seals, gray whale calves, or minke whales.
- Community: Live in small groups, create intimate bonds with members, and some offspring can live with their mother forever.
Offshore (the smallest and are more closely to Residents)
- Habitat: from Southern California to the Bering Sea
- Community: Live in big groups of more than 50 members
- Diet: Fish and Sharks.
North Atlantic Type 1 are generalist eaters. They eat seals as well as enormous runs of mackerel and herring in Scotland, Norway, and Iceland.
North Atlantic Type 2 are rare and huge orcas. They have characteristic back-sloping eye patches. These creatures mainly hunt dolphins and whales, especially minke whales.
b. Southern Hemisphere
Type A: These large killer whales have a size of up to 31 feet (9.5m) in length. They inhabit the wide regions of the Southern Ocean and eat minke whales.
Type B (large): or Pack Ice orcas
- Appearance: Because of diatoms (a form of algae) on their skin, the animals have a brown or yellowish look with a paler cape.
- Diet: Seals around Antarctica.
Type B (small): Gerlache orcas
- Habitat: In the Antarctic Peninsula’s Gerlache Strait.
- Appearance: Similar to the type B large
- Diet: Unknown, but they have been observed eating penguins.
Type C (Ross Sea orcas)
- Appearance: Males can grow to be about 20 feet (6m) long. The orcas have grey and white colors with a yellowish diatom covering. They wear a slanted eye patch. Their cape has the darkest color in the body.
- Habitat: Usually observed in heavy pack ice off the coast of Eastern Antarctica.
- Diet: Unclear, but it could be Antarctic toothfish
Type D (Subantarctic orcas)
- Habitat: Found in New Zealand.
- Appearance: Like other orcas, they have black and white color with saddle patch markings. Among those ecotypes above, they have the smallest eye patches. They also have shorter dorsal fins and rounder heads than the others.
- Diet: Unknown, it could be Patagonian toothfish.
Reference:
- 10 Facts About Killer Whales (Orca) – https://owlcation.com/stem/10-Facts-About-Killer-Whales
- The Killer Whale’s Killer Weapon — Its Brain https://www.pbs.org/wnet/nature/killer-whales-killer-weapon-brain/11352/
