Why does a narwhal need a strange uncomfortable horn?
Narwhal belongs to the cetacean family. However, it is distinguished from ordinary whales by a characteristic spiral tusk, similar to the horn of a unicorn.
The tusk looks thin and fragile against the background of a massive animal. It is inconvenient for the animal to attack with it, to defend himself from enemies too. Why did nature reward narwhals with this strange attribute?
Narwhals reach a length of up to 4.5 meters, and weigh up to 3 tons, of which a third is fat. The most characteristic feature of the narwhal is its impressive spiral tusk. But only adult males have such tusks.
The tusk grows up to 3 meters and weighs 10 kilograms! Some males have two tusks, usually one smaller than the other.
This is actually a tooth with all the nerve endings on the outside, not inside. The outer layer of the "tusk" is porous, the inner layer consists of tiny tubes that run to the middle. The pulp at the base of the tusk is riddled with nerve endings that connect to the animal's brain.
As reported in a study in The Anatomical Record, the mysterious narwhal tusk is full of sensitive nerve endings. Because of this, the narwhal tusk is sensitive to temperature and chemical fluctuations in the environment. Animals perfectly taste even the smallest concentration of chemicals in water. And they use the tusk-tooth to search for food.
Although scientists generally consider the tusk to be a male sexual characteristic, rare female narwhals also have a tusk (or even two, according to a doctoral dissertation by marine biologist Keith Hay of McGill University).
Why would a narwhal need a tooth outside?
Okay, let the tusk be a tooth. But why did it grow outside?
There are no functioning teeth in their mouths. In most males, the right canine remains in the skull and never grows, while the left canine breaks through the gums in a counterclockwise spiral, forming a long tusk.
The tusk is an essential survival tool for the narwhal. The animal can break ice on the surface with it. It also helps get food - pierce fish with the tusk and dig the seabed in search of food.
However, functionality recedes into the background. After all, most female narwhals do not have a tusk, and they live longer than males. Therefore, the main reason for the strange tusk is sexual characteristic, like the antlers of an elk or the tail of a peacock. These traits determine social rank and help the male attract a female.
Secretive like a submarine
Narwhal skin is variegated - black, gray and white on the back, more white on the belly. Whales are born predominantly gray, and with age they develop spots and blots. An old narwhal can appear almost completely white, making it hard to tell it apart from a beluga whale from a distance.
The heads of narwhals are relatively small and round compared to those of other cetaceans. Unlike whales, whose dorsal fins protrude from their backs, narwhals have a short ridge running along their backs. These short ridges make narwhals especially difficult to spot. It also floats very gently to the surface, which makes it difficult to find the animal.
Even the narwhal’s breathing is difficult to catch. While many whales come to the surface with a splash of condensed air, narwhals release a subtle puff of air.
Narwhal is an extreme animal
According to the World Wildlife Fund, narwhals live in the Arctic Ocean and off the coast of Canada, Greenland, Norway and russia. In summer, they can be found in coastal areas, and in winter - far out to sea. Narwhals are the only whales that winter in dense sea ice.
Other animals are rare here. Therefore, narwhals are an important source of subsistence for the Inuit, a culturally related indigenous group of Greenland, Canada and Alaska.
