Life in the water continues for two weeks/text

(Continued from the previous issue)

Origin of the name Pinniped

Pinnipeds are those whose limbs have evolved into fins. Seals, walruses, etc. are all pinnipeds, cetaceans were the first to adapt to the aquatic environment, followed by mammals. Many animals spend the vast majority of their lives in the water, visiting land only during feeding and giving birth. They get their name from their apparent limbs. The shoulders, forelimbs, thighs, and calves of pinnipeds are greatly shortened, and the fingers and toes are not only much longer, but also joined together by flesh or webbed, and the shape is similar to that of a fin.

Their bodies are streamlined like torpedoes, the outer ears are small or completely absent, and the nostrils can be closed. The thick layer of fat under the skin not only protects the body from the cold, but also enhances the ability to resist pressure in deep water. Because their bodies have been under the immense pressure of water for a long time, the bones of the body, especially the skulls that protect the brain, are very thick. Similarly, their fur adapted to life in the water and grew short and thick. The walrus's skin is barely hairy.

All pinnipeds look for stones on the seabed to eat. Stones help them grind the food in their stomachs and may also increase their weight so they can dive. Seals can dive to depths of 100-600 meters and stay underwater for 8-10 minutes. But when in a dangerous state, they can stay underwater for up to 30 minutes.

Amphibious predator

The otter wields freely in the water, rotates freely in the water, swims sideways, exposes its upper limbs vertically when "treading", or sleeps on its back on the surface of the water. However, otters are not aquatic animals, but amphibians. Otters hunt in the water and then come to land to eat, frolic and even sunbathe. Otters often travel long distances on land, crossing one river and then reaching another. The most adaptable to the aquatic environment of otters is the sea otter, which has some difficulty walking on land. Sea otters swim in a similar manner to seals, relying on their backwards extending hind feet and tail to propel the back half of its body up and down to swim forward. Sea otters normally dive for about 1 minute at a time, but up to 8 minutes at a maximum, with a depth of between 50-60 meters. Sea otters are picky eaters and choose to eat mainly sea urchins and mollusks. The sea otter uses one of its front paws to press the catch under its body to the surface of the water, then lies on its back on the water and begins to eat. The female sea otter gives birth to one cub at a time, which is well developed, the fur is thick, the first row of teeth is aligned, and the eyes are wide open. After the cub was born, the mother immediately taught it to learn to swim, and the cub was close to her body and dived into the water. Later, the mother left the cub on the surface of the water, holding a "life jacket" made of seaweed under her to escort it.

(End of full text)