More of China's male elephants reportedly are being born without tusks because hunting of the animals for their ivory is affecting the gene pool.

A study by Beijing Normal University indicates the tusk-free gene that's usually found in 2 percent to 5 percent of male Asian elephants is now found in 5 percent to 10 percent of the elephants in China, according to Zhang Li, an associate professor of zoology.

"This decrease in the number of elephants born with tusks shows the poaching pressure for ivory on the animal," Zhang told the Times of London. Zhang says he's been conducting research since 1999 at a nature reserve in the southwestern Xishuangbanna region, where two thirds of China's Asian elephants live.

Unlike African elephants, only male Asian elephants have tusks and the larger the tusks the male elephant has, the more likely it will be shot by poachers, Zhang told the Times. "Therefore, the ones without tusks survive, preserving the tuskless gene in the species."

China is one of 160 nations that signed a treaty in 1989 banning trading in ivory and the products of other endangered animals.

Copyright 2005 by United Press International