Is Poaching Causing Elephants to Evolve Without Tusks?
Spotting evolution can be trickier than you might think. Take African elephants. Usually they boast massively overgrown (and ever-growing) teeth—their tusks. For male elephants, these are weapons in sexual competition, but all elephants also use their tusks to scrape bark off trees, uncover roots, and dig for water during dry spells. Humans have their own use for tusks: ivory.
As a result, elephants have been subjected to centuries of hunting, and in recent years, aggressive poaching. The International Union for Conservation of Nature, which tracks the health of species across the world, estimates that elephant populations have shrunk by about 100,000 elephantsacross Africa since 2007, after an uptick in poaching starting around the same time. Since 2010, more than half of the dead elephants surveyed by an international monitoring program had been killed illegally.
Scientists have noticed that some elephant populations with a history of poaching show higher than expected rates of small or missing tusks, even in calves born after poaching ends. Does that mean elephants are evolving smaller or missing tusks in response to poaching? “I don’t think it’s a great stretch of the imagination to think that might be true,” says David Coltman, an evolutionary geneticist at the University of Alberta. He studies how trophy hunting affects bighorn sheep populations. “What’s difficult is identifying compelling evidence.” Full Story