Pinniped mammals: general characteristics

2024 Author: Henry Conors | [email protected]. Last modified: 2024-02-12 02:47

The pinnipeds order is a small group of about 30 species. There are three families:

• real seals;
• eared seals;
• walruses.

Carnivorous animals live mainly in water. They stay on land during certain life periods.

General Features

As already mentioned, the representatives of this group are walruses and seals. Let us describe their general characteristics. Pinnipeds are rather large animals with a maximum body weight of 3.5 tons and a body length of up to 6 meters. The elongated rounded body tapers towards the head and tail. The neck is thick and inactive, with the exception of eared seals. Most of the limbs are hidden in the body bag. A thick leathery membrane connects the fingers of the limbs, forming flippers. All this is typical for these mammals (order pinnipeds). Claws are developed differently in different animal species.

They use their limbs only for movement. With the help of the hind flippers, animals make oscillatory movements. In this case, the main muscle load falls on the back of the body. The front flippers balance the huge body and act as a rudder. The listed signs of pinnipeds indicate their adaptation to the aquatic environment.

The skin is thick with coarse hair. The subcutaneous fat layer reliably protects against hypothermia. The teeth of this class of animals are designed only for holding and grasping food. The brain box is large, the brain is large. External shells are absent, but their hearing is good. When immersed in the water surface, the auditory opening narrows due to the muscles. Pinnipeds can make barely audible sounds. The organs of smell are developed satisfactorily. Vision is practically absent. Vibrissae, which are long hairs, serve as the main organ of touch in animals.

Finding food, pinnipeds are able to stay in the water for a long time. The dimensions of the lungs are larger than those of terrestrial predators, and provide a complete exhalation and inhalation of a new portion of air. Lung tissue is elastic, thickened pleura, well-developed muscles.

The pinnipeds feed on crustaceans, mollusks, seabirds, and fish. Food is obtained only in the depths of the waters.

Walruses and seals prefer to rest on ice floes. Pinnipeds lead a herd life. The largest concentrations of animals are formed during the onset of reproduction and molting. Some prefer a settled way of life, others migrate.

Natural enemies are:

• sea leopards;
• polar bears;
• large sharks;
• killer whales.

Pinniped mammals come ashore or ice tomating and reproduction of offspring. At three years, puberty occurs. Usually one cub is born once a year. The body of newborns is covered with thick fur, which differs in color and structure from the fur of adults. After a few weeks, the fur of the younger generation changes. Babies grow up quickly, eating rich mother's milk. After the end of feeding, the cub becomes independent. Pinnipeds live up to 40 years.

Walruses

Walrus is one of the largest mammals of the pinniped class.

Representatives of this class can be found in the Chukchi Sea, near the archipelago of Franz Josef Land, off the coast of the islands of Novaya Zemlya, in the shallow seas of the Arctic Ocean.

Description

Walruses have powerful tusks of 2–4 kg each, which protrude 50 cm above the gum. In females, they are thinner and shorter. The main function of the tusks is to extract food by loosening the sandy or muddy bottom surface. Walruses in length can reach up to 4 m, and weigh 1.5 tons. Despite this body weight, these are mobile and agile animals. The entire body of mammals is covered with hard and sparse reddish hairs. Subcutaneous fat up to 10 cm thick reliably protects against hypothermia.

Walruses do not freeze in icy water and are not afraid of severe frosts. Due to the presence of a subcutaneous air sac, which is connected to the pharynx, they do not drown in water during sound sleep. On the upper lip there are thick, mobile and dense, locatedin several rows of vibrissa (sense organs). By the smell they learn about the approach of danger. They have poor eyesight. External auricles are absent. Nostrils and ear openings close tightly when immersed in water. Fins help animals dive and swim. The rear fins help push off the ground and ice.

Lifestyle

Rookeries are arranged on the ice floes or on the coastlines. In case of danger, they panic, rise from their homes and, crushing each other, go into the water, leaving behind the carcasses of dead animals.

Reproduction

Walruses breed from the age of five years once every three or four years. The walrus has one cub. The female feeds him until fangs (tusks) grow. She is a very caring mother and will never leave her cub in danger.

Threats

Uncontrolled walrus fishing led to a significant decrease in the number. Since the fifties of the last century, a ban has been established on their hunting. An exception was made only for the local population (Yakuts, Chukchi), who, under licenses, are allowed to hunt walrus in order to satisfy their personal needs. Some walrus species are included in the Red Book as endangered mammals.

Seal family

The elephant seal is the largest representative of pinnipeds among seals, lives in the subantarctic and subarctic seas.

It got its name due to the presence of a leathery bag, which is located in the nose of males. Most of my lifethe seal spends in the water. Males weigh more than three tons and are 6.5 m long. The weight and size of females depend on the genus to which they belong.

Pinnipeds are a commercial species of prey. The skins are used in the manufacture of shoes and clothing. The meat is eaten. The skins of young individuals are used as fur raw materials. Fur seals are in special demand.