Thank you for visiting my page. Please come again! As you may have figured out I LOVE seals. Seals are marine mammals that live in the sea. Although the seventeen different kinds of seals are found all over the world, most live in the Arctic and Antarctic. The group ranges in size from the ringed seal, which measures only 1.2 meters (4 feet) long and weighs about 68 kilograms (140 pounds) to the northern elephant seal, which may grow to be almost 6 meters (20 feet) and weigh up to 3600 kilograms (4 tons).
Seals, as well as sea lions and walruses, are called pinnipeds, which means "fin-footed". All pinnipeds have legs that are modified into flippers, an adaptation that makes swimming in the ocean easy and efficient. Another adaptation they have is a thick layer of fat, or blubber, that lies beneath the skin. The blubber insulates the animals and helps to keep them warm in the water.
Flippers and a layer of blubber make seals look different from other mammals, but they do share characteristics that distinguish mammals from all other animals. Seals maintain a constant temperature (are warm-blooded) and have hair or fur. Mother seals bear live young which they nurse with milk and care for until the young can take care of themselves.
Although the two groups are only distantly related, seals are often confused with the similar-looking sea lions. However, there are a few ways to tell them apart. First, true seals do not have external ears (like your earlobes or the ears of a dog). Instead, they simply have small holes that lead to the ear. The holes close when the seal dives underwater. Sea lions, however, have small earflaps on their heads.
Second, the flippers of seals are almost useless when they are on land. To move, they must wriggle along on their bellies. The front flippers are small and are used to turn and stabilize the animals in the water while their back flippers push them forward. They also help seals to haul out of the water and onto land. Sea lions, however, use their large and powerful front flippers to propel themselves through the water, and both the front and back flippers support the animals when they are on land. This makes sea lions agile creatures on land as well as in the water.
Like all pinnipeds, seals are carnivores and most feed on fish, shrimp, squid, and other animals which they chase out of the water, grab with their teeth, and swallow whole. The crabeater seal, though, strains small krill out of the water with comb-like teeth. Seals hunt primarily with their well-developed senses of sight and hearing. Very sensitive whiskers, vibrassae, can also be used to feel for shellfish on the ocean floor. Even though they are meat-eaters, seals in captivity will eat almost anything that is thrown to them. For this reason, aquarium and zookeepers must be very careful to make sure that nothing harmful is thrown into their pools.
Normally, seals do not dive very deep or stay underwater for more than a couple of minutes. However, some kinds of seals are able to dive as deep as 305 meters (1000 feet) and stay underwater for as long as thirty minutes when they hunt for food. How can they do this without running out of oxygen?
Scientists have learned that seals have more blood for their body size than land animals do. Because blood carries oxygen, seals have more oxygen
available to carry on life processes than other mammals do. When a seal dives, its heartbeat slows down from 120 beats to 10 beats per minute. This helps to conserve the oxygen supply in the blood. Another conservation measure involves shutting off the blood flow to most of the body. Instead, all of the blood flows to the organs that need oxygen the most, such as the heart and the brain.
Although seals live most of their lives in the water, they do come out onto land or ice to mate, bask in the sun, and to give birth to their young. During the breeding season, some seals form herds that can number anywhere from a few dozen to thousands individuals. Within these herds are large male bulls, female cows, and young seals, called pups. A male seal must defend his territory within the herd from other males through gestures and displays in order to keep the females in his harem from being stolen by other males. The more dominant males tend to have larger harems and appear to father more young than the subordinate males. Formal family groups are not observed in pinnipeds, normally the female bears the responsibility of care for the newborn pup.
Female seals give birth to a single pup once a year. Some pups are born with a thick wooly coat of fur which keeps them warm. This coat is shed after about a month, leaving the sleek adult coat. The seal pup grows very quickly because its mother's milk is forty-five to fifty percent fat. In comparison, cow milk contains four percent fat and human milk has two percent fat. The fat in seal milk is used to develop the blubber needed to insulate the seal from the cold water in which it lives. After only a short period of time (for some seals only two or three weeks) the young seal is ready to swim and feed itself.
Seals may live between twenty and twenty-five years, though the ringed seal commonly lives as long as forty-five years. However, many seals fall prey to other animals before they reach old age. Killer whales, sharks, and polar bears are all predators of seals. Their most dangerous enemies, though, are humans. People hunt seals for their fur, oil, and meat, and many also affect their habitat or food supply. Since 1972, seals living in United States' waters have been legally protected under the Marine Mammal Protection Act.
I really want to thank my teacher Mr. Montoya for helping me with this. MR. MONTOYA UR THE COOLEST!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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