As reported by Agencie France Presse for July 17,
[a] recent study has predicted that more male Asian elephants in China will be born without tusks because poaching of tusked elephants is reducing the gene pool, the China Daily has reported.Poaching may not seem at first blush to be an environmental pressure, but in the broad sense it surely is: The ivory of the tusks is what the poachers want. Large tusks, which in the absence of poaching are a favored characteristic for reproduction, become a risk factor in its presence - with the result that males with smaller or no tusks are more favored (or, perhaps more precisely, less disfavored) than they were before and so their proportion of the population increases.
The study, conducted in the Xishuangbanna Dai Autonomous Prefecture in south-west China's Yunnan province, where two-thirds of China's Asian elephants live, found that the tuskless phenomenon is spreading, the report said.
The tusk-free gene, which is found in between 2 and 5 per cent of male Asian elephants, has increased to between 5 per cent and 10 percent in elephants in China, according to Zhang Li, an associate professor of zoology at Beijing Normal University. ...
A similar decline in elephants with tusks has been seen in Uganda, which experienced heavy poaching in the 1970s and '80s, the report said.
That is, the doubling in the percentage of tuskless male elephants has come as a response to a form of environmental pressure. It's an illustration of evolution in action. A particularly cruel illustration based on greed - but evolution doesn't care: It's only concerned with maximizing survival.
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