The arval is a representative of the toothed whale suborder, belongs to the cetacean order, the narwhal family. Males have a long straight tusk. The appearance of the narwhal is unique, and the mind has a special development.
Appearance
The narwhal has a round head, not very large, with a protruding frontal part. The muzzle and nose are rounded. The whale does not have a dorsal fin, but there is a ridge on its back. Its length is 5 centimeters, and its height ranges from 60 to 90 centimeters. Adults are colored dark gray or brown from above, and the lower part has a lighter color. The whole body is covered with a mottled pattern.
The animal has no lower teeth. The upper jaw is equipped with two teeth. The left tooth of the male passes through the lip and continues in the form of a straight tusk. There is a spiral pattern on the tusk. The tusk can have a maximum length of three meters and reach a weight of ten kilograms. There are cases when the tusk grows out of the right tooth, but rarely.
Females do not have tusks, but sometimes they meet with tusks. The tusk is strong and flexible, it is able to bend in any direction, but it does not break. The tusk is polished at the end, and the part closer to the head is entangled with algae. The inner cavity of the tusk-horn contains the endings of nerve cells and blood vessels. The narwhal breaks through ice up to several centimeters thick with its tusk. If a narwhal’s tusk is broken, it won’t grow back.
The tusk is used by the narwhal for the following purposes:
· to attract females during the mating season;
· for measuring temperature and frequency of electromagnetic waves;
· As a weapon for loot or a baton for protection.
Male narwhals have a body length of about 450 centimeters, while females have about 400 centimeters. The average weight of males is 2.5 tons. The females are much smaller. Their weight can be almost 900-1000 kilograms. One third of the mass of the narwhal is fat, which serves as a reliable protection from the cold.
Lifestyle
Narwhals usually live in packs of several individuals, but sometimes there are up to twenty animals. Males and females with cubs gather separately in them. Narwhals constantly communicate with the help of harsh sounds in the form of: moans, grunts, clicks, gurgles. A distinctive feature of the narwhal is that the male has a long horn or tusk, about three meters long.
Narwhals live in the waters of the Arctic zone almost all year round. They migrate according to the movement of the ice: in winter they move to the southern zone, and in the summer season to the northern zone. In the summer, the narwhal lives in deep-sea areas, and winters in the water spaces between the ice. When the polynya freezes, the male destroys the ice barrier by striking with his back or tusk. Narwhals have a life expectancy of 35-56 years.
In the winter cold, the narwhal is saved by diving to a great depth, up to 1,500 meters. Periodically, it floats above the water surface to swallow air, then sinks back into the deep waters. During the day, the narwhal has to make up to 25 dives. The animal dives vertically, which allows it to achieve a higher diving speed. Also, a thick layer of subcutaneous fat protects the animal from low temperature.
In the spring and summer season, narwhals live at shallow depths up to 300 meters. Their food base is pack ice. In autumn, narwhals migrate to the southern regions located at 65-70 degrees north latitude.
Narwhals swim very well, but due to the lack of sufficient teeth, they feed on small organisms. They swallow them whole. The animal’s diet consists of crustaceans: squid, cuttlefish, octopus and fish: flounder, cod, sea bass, stingray, halibut, gobies. When hunting for prey, the narwhal holds its breath well and descends to a depth of 400 meters.
Reproduction
Mating in narwhals takes place from March to May. There is a showdown between males during the mating season. The winning male creates a small harem around himself and protects him from rivals. Copulation takes place with the bellies in an upright state. From July to August of the following year, the cubs are born.
The female’s pregnancy lasts about 15 months. The female reproduces offspring with an interval of two to three years. Usually one baby is born, but there have been rare cases of twins. The baby whale is born forward with the tail part of the body. As soon as the baby is born, the female immediately pushes him out of the water. He gets his first breath of air.
A newborn narwhal has an average body length of 1.6 meters and a weight of 80 kilograms. Subcutaneous fat is 2.5 centimeters thick. The baby’s skin is colored grayish-bluish. During the first days of life, the cub is constantly near the mother. Then the female can leave it on the surface of the water for a short time to absorb a portion of food.
The duration of feeding a cub by a female is 20-24 months. After the end of the lactation period, the cub leaves the mother and joins the youth group. Physical and sexual maturity in males begins at the age of eight, and in females it is formed by the age of five.
Population and conservation status
Narwhals are hunted by polar predators. Killer whales, polar bears, and polar sharks can ruthlessly kill them. Hiding from predators, the narwhal has to dive to great depths and hide under the ice. Also, the enemy of animals is man, he has been exterminating them for decades.
The number of narwhals, according to scientists, is about 50,000. It is difficult to give an exact figure, since they live in places that are difficult for humans to reach. So far, there has been no global decline in the number of narwhals, but the species is approaching the position of “vulnerable” and is classified as the third rare category. The narwhal was listed in the international Red Book.
The following reasons contribute to the extinction of the species: hunting of animals, predators, pollution of ocean waters. Due to the fact that the number of the species began to decline, narwhal fishing was limited: it is forbidden to take cubs and females, males are allowed only to the indigenous peoples of the north.
Special production quotas have been introduced in Greenland and Canada. Interstate and regional agreements have been adopted related to measures to preserve the ecological environment of the oceans.
