— Scientists from South Africa have for the first time recorded a case where one killer whale killed and ate a great white shark - previously it was believed that killer whales hunt sharks in groups. It took the killer whale only two minutes to deal with the formidable predator. Why do sharks, apparently, cannot even resist killer whales?
“Indeed, killer whales usually hunt in groups because they lead a family lifestyle.
But if for some reason one adult killer whale is left alone, without a family, it will survive calmly and will be able to get its own food.
South African scientists recorded a case where a large adult male killer whale caught a young white shark, whose body length did not exceed two and a half meters.
At the same time, the length of the killer whale was 6.5–7.5 meters.
Naturally, it was easy for him to deal with the shark with such superiority.
However, killer whales are undoubtedly very highly intelligent predators with flexible behavior.
They live in all oceans and almost all seas, except inland seas such as the Black and Azov.
Killer whales are highly adaptable to feeding on a wide variety of prey items, from schooling fish to large fish such as sharks.
There are also populations of killer whales that eat marine mammals, and Antarctic populations of killer whales even feed on penguins.
Therefore, biologists sometimes call killer whales sea wolves, which reflects the flexibility of behavior of these animals.
Like wolves, killer whales have mastered a variety of hunting methods based on coordinated group activity, which is the key to success.
At the same time, killer whales actively use echolocation during hunting.
Gettyimages.ru
© S_Lew
- But why, in this case, were they on the verge of extinction? In 2020, they were included in the Red Book by the Ministry of Natural Resources.
— Killer whales are the top of the food chain in the ocean, but this does not protect the species from extinction if the resources necessary to feed it are depleted.
As for the Red Book, not all killer whales are included in it, but the population of carnivorous killer whales living in the Far East.
At the same time, there are a lot of killer whale populations, their range is very wide, covering almost the entire World Ocean, and their actual numbers are currently unknown.
In our Far East, there are two populations of fish-eating and carnivorous killer whales.
The former feed on small fish, the latter on marine mammals.
The number of carnivorous killer whales in the Far East of the Russian Federation is not precisely known; the approximate average figure is 450 individuals.
The comparative paucity of carnivorous killer whales is explained by the fact that the marine mammals they feed on are also fewer in number than fish.
This determines the size of the predator population.
For example, southern resident killer whales, which live in coastal waters of Canada, are greatly affected by the depletion of chinook salmon (a subspecies of salmon) in the region, and accordingly the number of these killer whales is falling.
However, on a global scale, killer whales are doing very well; they are a prosperous species.
— Do carnivorous and fish-eating killer whales differ only in habits or genetically too?
- Today taxonomy classifies them as one species.
These populations may live in the same region, have access to the same resources, but due to established hunting traditions, one hunts for fish, and the other for mammals.
A population is a collection of animals of the same species that live in a specific area and have their own characteristics.
Thus, fish-eating killer whales living in the Far Eastern region have their own morphological features - the shape of spots, etc.
Killer whales attack baby sea lions
Gettyimages.ru
© Christian Peters
Fish-eating resident killer whales form larger groups, while transient carnivores live in small pods of up to 10 individuals.
Fish-eating and carnivorous killer whales differ in their vocal dialects, that is, they have different “languages” and do not understand each other.
Naturally, due to such serious “cultural” differences, killer whales from different populations do not interbreed with each other in nature, although physiologically they can bear offspring, since they genetically belong to the same species.
— How are pods of killer whales organized socially? Do they include only blood relatives or can alien animals be included? Do killer whales have a social hierarchy?
— In a group of killer whales, a strict hierarchy is observed; the female matriarch is always at the head.
Moreover, killer whales have a unique institution of grandmothers, just like humans.
After about 30–40 years, female killer whales enter menopause and lose their ability to reproduce.
However, they can manage the group for a long time, pass on hunting skills to the young, and the skills of caring for offspring to young females.
This is a very important and valuable institution.
At the same time, there is no struggle for the status of leader in a pod of killer whales; the female matriarch usually fulfills her duties until the end of her life.
Only after her death is her place taken by a daughter or granddaughter who remains in the group.
I note that group structure differs greatly in different populations.
Thus, among resident fish-eating killer whales, young females often remain in the group, so they form numerous pods.
And among carnivores, the offspring, as a rule, leaves the mother - young killer whales either create their own groups or join other small families.
Of course, only carnivores - carnivorous individuals cannot join a group of resident killer whales, they simply will not understand each other.
Gettyimages.ru
© Jeff Foott
—What social role do males perform?
“Male killer whales, of course, take part in social interactions within the group, but do not have the “right to vote.”
Moreover, males tend to be dependent on their mothers.
It has been proven for a number of populations that the chances of survival of an adult male killer whale decrease if his mother dies.
— You talked about the “cultural” differences between fish-eating and carnivorous killer whales, but are there any geographic specifics? Will a carnivorous killer whale understand another, also carnivorous, but from another part of the World Ocean?
- No, he won’t understand, they have different “languages” of communication that are formed within a specific group, they can be roughly compared with different human languages.
Carnivorous killer whales are quieter, more silent - this is necessary so that their prey, marine mammals, do not hear them.
For example, seals themselves use ultrasound, so they can hear the sounds made by killer whales.
Gettyimages.ru
© Cavan Images
But fish-eating killer whales can afford to “chat”, since fish generally do not hear sounds in the ultrasonic range.
— What is the “language” of killer whales?
— All toothed whales are capable of making three main types of sounds: clicks, squeaks and whistles.
Clicks are used for echolocation, and creaks and whistles are used to communicate with each other.
We don't yet understand this communication system.
It is known that, like human children, killer whales master “language” as they grow older, they learn to make different sounds from their relatives.
Small cubs have a small range of sounds.
It is also known that female killer whales have “lullabies” - sounds that she begins to make after the birth of a calf and which are addressed only to him.
— Killer whales are famous for their intelligence and ability to develop entire tactics for successful hunting. For example, they can create a wave that washes a seal off an ice floe. What other interesting and unusual habits have scientists observed in killer whales?
— Killer whales have many interesting tactics.
For example, those that feed on sea lions and fur seals disperse and are thrown ashore after them, and then return to the sea with their prey.
And fish-eating killer whales have mastered and practice “freeloading” - they regularly eat halibut lines set by fishermen.
Halibut is a deep-sea fish that is caught on a very long line with bait.
The longline is dropped to the bottom, the halibut is caught on the hooks and then the line is raised to the surface.
And at this moment, the killer whales eat part of the catch, sometimes half of all the fish caught.
Of course, the fishermen are not happy with this situation; to put it mildly, they are trying to come up with ways to scare off the killer whales.
However, killer whales, like other toothed whales, are highly intelligent animals that can assess whether there is real danger to them or whether they are simply being scared away.
Gettyimages.ru
© Mark Gibson
— How stable are the hunting traditions of killer whales? Can, for example, different pods of fish-eating killer whales learn something from each other, and also improve the adopted tactics?
- Of course they can, they learn very successfully from each other and adopt other people’s inventions, so to speak.
This allows killer whales to increase their hunting efficiency, explore different ecological niches and different types of prey.
Moreover, cases of collaboration between killer whales and people are reliably known.
In the 19th and 20th centuries, whaling was developed off the coast of Australia; whalers hunted right and humpback whales, as did killer whales, for whom these animals are also prey.
As a result, people and killer whales joined forces: the killer whales drove the whales closer to the shore, where whaling ships were waiting for them.
After the whale was harpooned, the whalers left its carcass at sea for a day, allowing the killer whales to eat the lips and tongue - a favorite delicacy of these sea predators.
People were only interested in whale oil.
This cooperation continued off the coast of Australia for about half a century.
— Why don’t killer whales perceive people as prey? How do ethologists explain cases when killer whales attacked yachts - was it a game or aggression?
— As for attacks on yachts, this is how young killer whales play.
They have no goal of harming people, but during the game they even overturned ships, which, of course, poses a danger to people.
It is not yet clear how to solve this problem, because it is difficult to scare off killer whales; they practically know no fear, since they have no natural enemies.
However, killer whales do not perceive humans as food, primarily because they do not have such a hunting tradition.
The grandmothers and mothers of killer whales did not teach them to hunt people, so it does not even occur to them to perceive a person as a food item.