Tuesday, August 20, 2019
Whales Essay -- essays research papers fc
Whale weighs as much as 20 elephants but lives beneath the sea. The blue whale is Earth's largest animal. Larger than the largest of ancient dinosaurs, blue whales can grow to be more than 100 feet (30 meters) long and weigh nearly 150 tons. Not all whales are so large. The much smaller pilot whale grows to about 28 feet (8.5 meters) in length. And dolphins, which belong to the whale family, range only from 3 to 13 feet (1 to 4 meters). Although whales spend their lives in the sea, they are, like humans, warm-blooded mammals. After a baby whale is born, it nurses on its mother's milk, just like the young of land mammals. Whales are members of the order Cetacea, along with dolphins, porpoises, and the narwhal. There are two basic types of living cetaceans: baleen, or whalebone, whales of the scientific suborder Mysticeti; and toothed whales of the suborder Odontoceti. General Characteristics Whales live in all of the open seas of the world, though some occasionally enter coastal waters. Some species, such as the white whale, or beluga, may travel upstream in large rivers. Some species migrate with the seasons; others remain year-round in the same habitats, where they find their preferred food. The present-day distribution and abundance of some species has been greatly influenced by the commercial whaling industry. Whalers eliminated or greatly reduced the numbers of some species of baleen whales in certain oceanic regions where whales once frolicked in abundance. This is particularly true in parts of the Arctic Ocean and the eastern North Atlantic Ocean, where the blue whale was almost completely exterminated in the early 1900s. Some species of whales, however, are numerous today in the Arctic and Antarctic regions. The skin of whales is usually black, gray, black and white, or all white. Some, such as the blue whale, have skin that is bluish-gray. The surface of the skin is smooth, but like other mammals, whales have hair. Hair first appears while the fetal whale is still developing inside its mother's womb. In adult whales, hair is confined primarily to a few bristles in the head region and is largely absent over most of the body. Whales that live in polar regions are insulated from the extreme cold by a layer of blubber, or fat, enveloping their bodies. Baleen Whales The baleen whales inc... ...usion In 1946 the International Whaling Commission (IWC) was established to set up the guidelines followed by whaling nations today. The sizes, kinds, locations, and seasons of catches are controlled. However, strong international politics came into play, and some nations steadfastly voted against, or even ignored, restrictions that were not economically advantageous. The limitations were passed almost too late for the blue whale, which had already declined to dangerously low numbers in all oceans. The once large populations of blue whales in the eastern North Atlantic were almost brought to extinction. Today, fewer than 500, and possibly as few as 100, are found there. In 1971 the United States declared all commercially exploited whales endangered species and made it illegal to import any whale products. The United States lists the blue, bowhead, finback, gray, humpback, right, sei, and sperm whales as endangered species. Therefore, we should take goof care of whale. Works Cited Cousteau, Jacques, and Paccalet, Yves. Whales (W.H. Allen, 1998). Tinker, S.W. Whales of the World (Bess Press, 1997). Day, David. The Whale War (Sierra Club Books, 1997).