Pinniped mammals: general characteristic

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

• Real seals;
• Eared seals;
• Walruses.

Predatory animals live mainly in water. On land are in certain life periods.

General characteristics

As already mentioned, the representatives of this group are walruses and seals. Let us describe their general characteristics. Pinnipeds are quite large animals with a maximum body weight of 3.5 tons and a trunk length of up to 6 meters. An elongated, rounded body narrows toward the head and tail. The neck is thick and inactive, with the exception of eared seals. Most of the extremities are hidden in the trunk sac. A thick leather membrane connects the fingers of the limbs, forming fins. All this is typical for these mammals (order pinnipeds). In different species of animals claws are unequally developed.

They use their limbs only for movement. With the help of the rear fins, animals vibrate. Thus the basic muscular load is necessary on a back part of a body. Front fins balance a huge trunk and perform the function of the helm. The listed signs of pinnipeds indicate their adaptation to the aquatic environment.

The skin is thick with stiff hair. The subcutaneous fat layer reliably protects from hypothermia. The teeth of this class of animals are intended only for keeping and grasping food. The cerebral cortex is large, the brain is large. There are no external shells, but they have good hearing. When immersed in the water surface, the auditory opening narrows, thanks 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 for the sense of touch of animals.

Getting poultry, pinnipeds mammals are able to stay in the water for a long time. The size of the lungs is greater than that of the terrestrial predators, and provide a complete exhalation and inhalation of a new portion of air. Pulmonary tissue is elastic, a thickened pleura, developed musculature.

They feed on crustaceans, shellfish, seabirds, and fish. Food is extracted only in the depths of the waters.

Walrus 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 sedentary lifestyle, others migrate.

The natural enemies are:

• Sea leopards;
• White bears;
• Large sharks;
• Killer whales.

Pinnipeds mammals come ashore or ice for mating and reproducing offspring. At three years, puberty begins. It is born mostly one cubs once a year. The body of newborns is covered with thick fur, which in color and structure differs from the fur of adults. A few weeks later the fur of the younger generation is changing. The children grow quickly, feeding on the fat milk of the mother. After the end of feeding the baby becomes independent. Pinnipeds live 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 coasts of the New Earth Islands, in the shallow seas of the Arctic Ocean.

Description

Walruses have powerful tusks of 2-4 kg each, which protrude above the gum by 50 cm. In females, they are thinner and shorter. The main function of tusks is to harvest 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 thickness of up to 10 cm reliably protects from hypothermia. Walruses do not freeze in icy water and they are not afraid of steep frosts. Due to the presence of a subcutaneous air sac, which is connected to the pharynx, they do not sink in water during a sound sleep. On the upper lip there are thick, mobile and dense, located in several rows of vibrissae (sensory organs). By smell they learn about the approach of danger. Have poor eyesight. There are no external auricles. Nostrils and ears open tightly when immersed in water. Fins help the animals to dive and swim. Back fins help to repel from the surface of the earth and ice.

Lifestyle

Roosts are arranged on ice floes or on shorelines. In case of danger, they panic, rise from their own places and, after crushing each other, go into the water, leaving behind the carcasses of dead animals.

Reproduction

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

Threats

An uncontrolled harvest of walruses led to a significant decline in numbers. Since the fifties of the last century, their hunt has been banned. An exception was made only for the local population (Yakuts, Chukchi), which are allowed under licenses to hunt for walruses in order to meet personal needs. Some species of walrus are included in the Red Book as endangered mammals.

Seal family

The sea elephant is the largest representative of pinnipeds among the seals, inhabits subantarctic and subarctic seas. The name he received due to the presence of a leather bag, which is located in the nose of male individuals. The seal spends most of its life in the water. Males weigh more than three tons and have a length of 6.5 m. The weight and size of females depend on the genus to which they belong.

Pinniped mammals are a commercial species of prey. Skins are used in the manufacture of footwear and clothing. Meat is used for food. Skins of young individuals are used as fur raw materials. Special demand is for fur seals.