Whales Essay Research Paper IntroductionWhale is a — страница 2

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tail are different for each whale so it is similar to fingerprints of human. Because of this, new form of research known as photo- identification was made. Each whale is identified, catalogued and monitored so this gives researchers valuable information about humpback whale population, migration, sexual maturity and behavior patterns. Adult humpback measure 40 to 48 feet in length and weigh about 30 tons. Humpback whales are found in all the world s oceans. Most populations of humpback follow a migration routine, summering in temperate and polar waters for feeding and wintering in tropical waters for mating. Because their mating, feeding and calving grounds are close to shore, they were the target for early hunters. But in 1966, the IWC- International Whaling Committee gave them

worldwide protection. At present, there are about 15,000 humpback whales living, which is around 15% of the original population. Blue Whale The blue whale is also one of the rorquals. On land an animal the size of a blue whale would be crushed by its own weight without the support of large heavy bones. But because its body is supported by water, there were no needs for such large supporting bones. Also with the availability of large food supply have made it possible for blue whale to reach an enormous size. This is why the blue whale is the largest animal ever to live. Blue whales are scattered all over the world but the northern and southern populations do not mix. They migrate to temperate waters from their polar feeding grounds at different times of the year. The blue whales

was nearly exterminated until it received a worldwide protection from the IWC in 1967. Most of the remaining blue whales are known as Pygmy blue whales while there are about 400 true blue- whales- ones that can be 100 feet in length- that shows no sign of recovery. It is said that approximately 5000 blue whales survive today in three primary locations; North Atlantic, North Pacific, and the Southern Hemisphere. Right Whale There are two groups of right whales. The first group is the Northern Right whale, which has the title of the most endangered great whale with less than 1000 existing. Northern right whale has shown no signs of recovery since the whaling days despite full protection from hunting by a League of Nations agreement in 1935. Some believe that eastern north Atlantic

population may already have become extinct while western North Atlantic population has as many as 300 remaining. The other right whale, the Southern right whale lives only in the southern hemisphere and never mixes with northern right whale. Southern right whales mate during the winter in the inshore waters of Chile, Argentina, Brazil, Africa, Southern Australia, and other southern islands then migrate to water near Antarctica to feed during the summer. Southern right whale have the status of vulnerable with about 1500 to 4000 remaining. The most serious threats to right whales survival today are the collision with ships and entanglement in fishing gear. In 1999, there was one known death from each of these causes. Right whales are 35- 60 feet in length and weigh about 50 tons.

Bowhead Whale The bowhead whale is also known the Greenland right whale and is similar to Northern right whales but a little different. It received its name from the high arched lower jaw that resembles the shape of an archer s bow. Bowheads live at the southern edges of the Arctic during winter and moves into areas with melting ice during summer. Found only in Arctic and sub Arctic water, the bowhead has a massive body, which is protected by two feet thick blubber. As an adult, it can be fifty feet long and weigh 60 tons. Bowhead usually travels alone unless they are in the feeding ground. It is said that one bowhead can yield up to 100 barrels worth of oil and 1500 pounds of baleen (whalebone). At present, the number of bowhead is estimated around 6000. Gray Whale Gray whales

are coastal whales that migrate along the North American Pacific coast between arctic seas and the lagoons of Baja California, Mexico. Frequently visible from shore, gray whales provide a unique opportunity for land and boat observation, and commercial whale watching has become a major industry along its migration route. Gray whales are known to be friendly and closely approaches small boats so that it can be touched by humans. The gray whale receives its name from the gray patches and white mottling on its dark skin. Adult gray whales measure 45 feet and weigh about 40 tons. Killer whales are a cause of many gray whale deaths and many gray whales have killer whale teeth scars on their body. At one time, there were three gray whale populations. A north Atlantic population now