CHỦ ĐỀ 3: ĐỘNG VẬT PHẢI ĐỐI MẶT VỚI TUYỆT CHỦNGOver a thousand species of animals are threatened with extinction, and humans are directly or indirectly to blame. Most of the big cats - lions, tigers, panthers, leopards and cheetahs - have 5 been hunted for thousands of years, sometimes to protect livestock, but more often for sport or for their skins. The Asiatic Lion once inhabited a vast area from Israel to India; now only a few hundred remain, under strict protection, in the Gir Forest of India. The Barbary Leopard, once found throughout North Africa, is even rarer: no more than 50 exist. The Bengal Tiger has been much luckier; thanks to strict measures taken in 1972 by the Indian Government, it is now thriving. Hunters - or rather poachers, since their victims are under legal protection -also threaten elephants, killed for their ivory tusks, and rhinoceroses, whose horns are used to make traditional Chinese medicine and handles for Yemeni daggers. The situation regarding rhinos is particularly desperate: fewer than 8,000 remain in Africa, just over 1,000 in North India and even fewer in Indonesia. Many of the primates are also suffering from human aggression, but the main cause of their decline in numbers is environmental. Deforestation has severely reduced the natural habitat of the Orang-Utan in Sumatra, the Golden Lion Tamarin in Brazil, the Lion-tailed Macaque in India and the Red Lemur in Madagascar, to name just a few of the worst cases. The panda's greatest enemy is its own natural vulnerability. Not only is it dependent on a single source of food - a special kind of bamboo which suddenly flowers and then dies once every 60 years - but it also has great difficulty breeding, especially in captivity. Even if it could be completely protected from poachers, who face the death penalty if caught, and from encroachment by loggers and farmers, it may become extinct, as fewer than a thousand now remain. Marine animals face three main dangers, all resulting from human activity. Some types of whale have been hunted almost to extinction for their meat, oil and bone. The blue whale, the largest mammal in the world, has become one of the rarest, owing to the use of radar by modern whaling ships. Dolphins often swim with tuna and tend to get caught in the large nets used by many tuna fishermen. The largest of these nets, known as drift nets, catch all sea creatures indiscriminately, resulting in serious depletion of fish stocks as well as the loss of dolphins and other marine animals. For the inhabitants of shallow coastal waters, pollution is a major hazard. The disappearance of the Monk Seal from the Caribean Sea may be attributed both to pollution and drift-net fishing.
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