Toothless gene in the spread of Asian elephants in the
When ivory into death flag, Asian elephants have transformed — — —
As long as the sword Trident is male Asian of ivory as a symbol of the strong, but now, Asian elephant population, hung as fewer and fewer, more surprisingly, few hung like, actually appeared more and more toothless male elephant. This is the natural evolution of results, or select Asian elephants helpless?
Ivory became the symbol of Asian elephants killed, toothless, as more and more.
Ivory has been viewed male elephant symbol of strength, the two long, curved incisor teeth, in addition to being hung like as fighting weapons, they get a female elephant favor capital. But for Asian elephants, has a huge ivory will no longer be a bragging, but become a sign of death.
Asian elephant family only male have ivory, ivory trafficking of enormous profits also let greed of poaching are evil gun a male elephant. Human records of ivory weigh as much as 97 kg, but due to poaching we now difficult to find weight of more than 45 kg of ivory.
In the country, the most rampant poaching Asian elephants in the 1980s to the mid-1990s, in one of two large-scale poaching, a total of nearly 30 head Asian elephants killed. In 1990, promulgated by the international ivory ban was once so rampant ivory smuggling has eased, but the elephant from tooth of crime has not yet been eradicated.
"At present, China's population of Asian elephants only about 250 head, of which there are about 200 head in Yunnan Xishuangbanna. "Zhang, Ph.d., told reporters. Zhang, Dr., Associate Professor of Beijing Normal University, the International Fund for animal welfare, on behalf of the Asian elephant project in China. Since 1999, Zhang began with a post graduate in Yunnan wild Chase in the footsteps of the Asian elephant.
In addition to the male elephant numbers decimated, even more surprising is the fact that elephants in ivory-like more and more. Zhang, Dr. said: "in India a nature reserve, not long ivory-like 20% can be achieved. We at Yunnan Xishuangbanna also found no tooth-like. ”
What causes male Asian elephant transformed? is this is the result of population natural evolution?
Toothless, as more and more, is the choice of Asian elephants helpless.
"In fact, toothless gene in Asia as the body is always exist. Dr. explained: "Zhang" nature has 2% to 5% of the male Asian like born not of ivory. But now the Asian elephant population in toothless hung like a proportion substantially exceeds the normal range, toothless gene in the male elephant populations spread, it's against the law of nature. ”
Hung like long ivory is a normal result of natural selection. Ivory is hung like to fight, a powerful tool for spouse, is hung like a strong symbol. The larger the male elephant ivory in contention for the spouse of the fighting during the more able to easily win, gain and female elephant mating rights. If in full accordance with the laws of natural evolution, the male elephant ivory and ivory, the larger male elephant will own gene reserves the likelihood of genetic indefinitely, no ivory-like will be eliminated.
But now the situation on the contrary, due to poaching, the male elephant ivory and ivory, the larger male elephant more vulnerable to hunt, toothless male elephant is preserved. This toothless gene has been preserved, there is a gradual loss of tooth gene. This is not a natural evolution, but Asian elephants in the face of poaching ' muzzle made of choice.
Hung like decimated, inbreeding increases, more and more vulnerable populations of Asian elephants.
Poaching of males like killing, not only for Asian elephants of ivory disappear, even more serious consequence is the Asian elephant promoted genocide. The male elephant ivory, generally within 12 to 14 years old when the President, and this time also happens to be hung like a sexual maturity period, but they haven't had a chance to be mated, murdered and poaching ' bloody killing.
"At present, the Chinese discovered in the wild can make individual identification of adult male elephant has less than 20 head. "Zhang, Ph.d., told reporters. And because the number of adult male elephant, many male elephant ivory have not fully grown it has been hunted. Asian elephant sex ratio imbalance, it is for the Asian elephant species is very dangerous.
In India a South Asian elephants nature reserve, with 400 head female elephant, but only 4 head hung like participation in propagation, as a result, the population of offspring is this 4 head hung like offspring. China Yunnan nangunhe region a 20 long Asian elephant population, only two male elephant. Due to long-term inbreeding, Asian elephants genetic diversity continuously forfeit, very easily lead to a large number of extremely fragile, even do not have the ability to reproduce. This makes Asian elephant populations are becoming increasingly vulnerable.
A richness of species gene implies life to adapt the environment changes. Even if the environment changes dramatically, some genes may play a role and sustain life. Such as insects, faced with the variety in nature and does not exist in the artificial insecticides, always a few insects survive and subsequently reproduce themselves produce resistance to future generations. Therefore, genetic diversity can be said to be species survival in the face of nature changes or not.
Lack of genetic diversity of species, and environmental changes or specific diseases are particularly vulnerable, slightly accident could result in the death of massive population. While initially was selected strong male animal genes, in propagation of several generations later, often lose their superiority, to improve the quality of future generations.
Habitat into ecological Islands, Asian elephants facing natural threat of extinction.
In addition to the Asian elephant poaching, devastating disasters were caused by species of human activity. "We see in the wild, farmland, cultivated land, rubber plantations, etc., the Asian elephant Habitat become fragmented, Asian elephants living in one of this
Samples of ecological island. "Zhang, Ph.d., told reporters.Asian elephants are usually groups activities by female like steer a baby elephant. Asian elephants in food intake, daily to eat about 300 kg of fresh fodder, elephants lot… for food sources. In order to survive, elephants run daily to 18 to 20 hours. Hung like General grow to 10 years old to 14 years of maturity, they will leave the elephants, and began to walk alone. Estrous season coming, elephants will catch up with the female elephants mating, complete, and then left again.
But now, Asian elephant habitats being artificially isolates, dams, rice fields, rubber plantations, etc. become elephants impassable artificial barriers. Walk out-like the quarantined in population, could not find the female elephants, a female elephant nor and male mating breed, like an elephant in no baby elephant was born.
Zhang, Ph.d., they found the field observation, Simao region a population of Asian elephants, from 1996 to the present, nearly ten years had no male elephant population involved in reproduction, like the female old, day by day without a baby elephant was born, this population might naturally perished.
Background knowledge
About the Asian elephant
Asian terrestrial mammals like the Asian continent in the biggest of all is dark grey or brown skin disperses lives with hair. Adult male Asian elephant shoulder high about 2.4 m to 3.1 meters, weighing about 2700 kg to 5000 kg. A little like the female figure.
Our history has been a very Asian elephants resource-rich countries, half of the country have a trace of the Asian elephant. In 3000-3500 years ago, Asian elephant distribution of North Limited is located in Yellow River North of Hebei yangyuan area, and the short title of "Henan Henan" Word is a staff led by the Asian elephant.
There was also a tayu ploughing with Asian elephants, legend has it that for livestock rearing is used as a riding, farming, handling and as a tool of war. Oracle also has a number of Asian elephants in the record, such as the "Palace in the rain, an elephant," "to like John Yoo (Woo) b", etc. Shang dynasty Henan area climate was warmer, suitable for the survival of the Asian elephant, unearthing in Anyang has unearthed a large number of ivory and ivory ornaments. Future climate change, gradually migrates South Asian elephants. In the Tang dynasty, it is also widely distributed in Guangdong, Guangxi, Fujian, Jiangsu, Zhejiang, etc. along the Yangtze River basin. But since then, under the pressure of the people, Asian elephants in the distribution area began to narrow gradually moved south. South Asian as extinct in the 12-13th century, Lingnan and Guangxi in Asia as extinct in the 17th century.
Now the distribution to our Asian elephants in Xishuangbanna Yunnan lincang and Simao, and parts of South Asia, Southeast Asia. Asia seems to be included in the international CITES endangered species of animals and wild animals in our country level, the country is now the only remaining more than 250.
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