Why do animals become extinct?
Since the time animals have evolved species continue to become extinct. The most well-known example of extinct species is that of the dinosaurs. Often the species cannot adjust fast enough to the changing environmental conditions, or new species arise and displace the existing ones. Today, many species are becoming extinct because of the actions of humans. Elephants, big cats, and rhinos are hunted ruthlessly, forest areas are cleared, and the grey whales are endangered. These are only a few of the species mentioned in the 'Red List'. On a positive note, new animal species are also being discovered.
Why are elephants hunted?
Elephants are hunted for their tusks. These are made of ivory and were used to make jewellery sold at high prices. Many elephants were shot for their tusks, and even today they have to be protected from poachers in wildlife parks. Other animals are also hunted for their body parts. The Asian black bear is hunted for its gall bladder, rhinos for their horns, seals and big cats for their skin. A few wild species of crocodiles are killed because their skin is used for making bags and shoes. Hunting is also done for the thrill of the chase and a greed for the trophy, such as a bear or tiger skin.
What is threatening the grey whales?
The grey whale lived around 300 years ago in the Atlantic and Pacific Oceans. The giant animals were hunted extensively for their meat and oil. They became extinct in the Atlantic by the end of the 17th century, but can still be found in the Pacific Ocean. Around 20,000 animals migrate every year in October from Alaska in the north to the coast of Mexico, where they give birth to their young ones in winter. In west pacific, there are at most 200 grey whales at present and they are listed as critically endangered. These animals are sensitive to noise and are being displaced from their habitat because of the construction of drilling rigs for the crude oil industry.
Customs officers in Africa repeatedly come across large quantities of elephant tusks during their checks.
The grey whale is one of the largest mammals on Earth. It feeds extensively in summers and eats only small crabs and fish. The fat reserves built during the summer months are used as an energy source during their winter migration and reproduction.
What is the'red list'?
The list of endangered species is known as the Red List. It lists all those plant and animal species that are facing the threat of extinction worldwide. The list is revised every 2 years. For the year 2006, the list contained around 16,000 species of plants and animals; 530 species more than the list for 2004. One-fourth of all the mammals are present in the list. All species of elephants, rhinos, gorillas, orangutans, chimpanzees, most species of whales, and half of all vertebrates living in freshwater are also part of the Red List.
Why did dinosaurs become extinct?
Dinosaurs existed on Earth 65 million years ago. Today, the scientists believe that their mass extinction was triggered by a huge meteorite hit to the east of Mexico. The meteorite impact caused blasts and flood waves. Huge quantities of poisonous gases filled the Earth's atmosphere. Then there was acid rain that polluted the seas and the plants died. Huge dust clouds blocked the heat from the sun and it became cold. The cold-blooded dinosaurs became sluggish and starved. Young ones did not hatch from their eggs. Only the small animals, which adapted themselves quickly and did not need a lot of food, survived.
Where are new animal species discovered?
Scientists often come across new species of animals in areas that are difficult to access for humans, such as mountain peaks, caves, deserts, rainforests, and the depths of the oceans. In the tropical rainforest itself, new species of insects and spiders, and also other animal species, are being discovered regularly. To explore the tops of giant trees, biologists use mountaineering equipment kept in a tree house on the top of the trees.
Write to a conservation society such as the WWF (World Wildlife Fund for Nature) and request them to send you the Red List for the state in which you live. The list for some states is also available on the Internet. Which of the endangered animals do you know? Which of these are living in your surroundings? Two dinosaurs: On the left is a 190-million-year old fossil of an unhatched dinosaur, and on the right is the full-grown shape of the young one.