Tuskless elephants evolve

[Soxy]

Holy cow, this is cool!!!!

Tuskless elephants evolving in China due to poaching

 

Sun Jul 17, 3:59 AM ET

 

BEIJING, July 17 (AFP) - 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 reported Sunday.

 

The study, conducted in the Xishuangbanna Dai Autonomous Prefecture in southwest 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 two and five percent of male Asian elephants, has increased to between five percent and 10 percent in elephants in China, according to Zhang Li, an associate professor of zoology at Beijing Normal University.

 

"This decrease in the number of elephants born with tusks shows the poaching pressure for ivory on the animal," said Zhang, whose research team has been studying elephants since 1999 at a reserve in Xishuangbanna.

 

Only male elephants have tusks, which are said to be a symbol of masculinity and a weapon to fight for territory. However, due to poaching for ivory, the elephants' pride has become a death sentence, the report said.

 

"The larger tusks the male elephant has, the more likely it will be shot by poachers," said Zhang. "Therefore, the ones without tusks survive, preserving the tuskless gene in the species."

 

A similar decline in elephants with tusks has been seen in Uganda, which experienced heavy poaching in the 1970s and '80s, the report said.

 

However, Zhang's findings of the spread of the tuskless gene due to poaching must be tested, according to some academics.

 

"This is, of course, a possibility, but till now there is no clear genetic proof that it can occur," Vivek Menon, executive director of the Wildlife Trust of India, was quoted as saying.

 

Rampant poaching of male elephants for tusks has also caused the female-to-male ratio to rise from the ideal 2:1 to 4:1 in China and 100:1 in India, the report said.

 

There are between 45,000 and 50,000 Asian elephants in 13 countries, including China and India. China only has about 250, according to the report.

 

China is among 160 nations which signed an international treaty administered since 1989 banning the trade in ivory and products of other endangered animals.

 

Nonetheless, four Asian elephants were found shot dead in China last year.

 

In addition to poaching, human activity that causes a loss of habitat also threatens the animals.

[Balta1701]

I heart natural selection.

[FlaSoxxJim]

I heart natural selection.

As do I. But in this case it is artificial selection apparently pushing the bell curve to the left and increased incidence of lack of tusks. Just like overfishing of the large adult fish has artificially selected for animals with a smaller mean size to reproductive maturity, humans culling the would-be top breeding males in the population has allowed less fit variants with to get their tuskless genes into succeeding generations at a greater frequency.

 

The guy in the article who said the hypothesis needs to be tested is correct, but at only a couple hundred animals in the China population, this may very well be a case where a 'founder effect' can occur and where the rare no-tusk alleles are not swamped by the wild type alleles of the more fit variants. Similar to the cases of frequent polydactyly in some highly in-crossed pocket of humans.

 

And, Soxy, you've broken my heart.

 

That would be an automatic letter grade deduction in one of my classes

 

"Elephants evolve to combat poaching"? Aaaagh!! That suggestion is way too teleological for my tastes. How about "Rare population characteris increase as a result of anthropogenic selection pressure"? Yes, that's better, I think.

[Soxy]

And, Soxy, you've broken my heart.   

 

That would be an automatic letter grade deduction in one of my classes

 

Sorry. I knew I should have paid more attention during the evolutionary part of my bio classes.

[FlaSoxxJim]

Sorry. I knew I should have paid more attention during the evolutionary part of my bio classes. 

I'm just thankfull your bio classes still had an evolutionary part...

[Soxy]

I'm just thankfull your bio classes still had an evolutionary part...

Lol, at St. Olaf College no less! Where more religion classes are required than hard science and math.

[LosMediasBlancas]

I think it's kinda sad and not cool at all.

[Balta1701]

Yes, you're right on the artificial selection point. I'll attribute it to the fact that it was roughly 11:30 when I posted that.

 

This one, btw, is absolutely beautiful.

 

"Elephants evolve to combat poaching"? Aaaagh!! That suggestion is way too teleological for my tastes. How about "Rare population characteris increase as a result of anthropogenic selection pressure"? Yes, that's better, I think.

[FlaSoxxJim]

I think it's kinda sad and not cool at all.

What, the decimation of an elephant population almost to the point of inviability? Yes, that is enormously saddening, of course.

 

But, from the observational standpoint of seeing the (likely) results of directional artificial selection over the course of a few generations it is compelling evidence that the population (and others like it) need more protection. An added ironic twist that Soxy, and Balta recognize here, though, is that the poaching has taken many of the fittest male variants out of the breeding pool and the apparent result is an increase in the frequency of tuskless males born into the population – poetic justice because they will be of no value to ivory poachers.

[RibbieRubarb]

::Note to self::

 

Cancel Christmas trip to China...