Poaching may have forced female elephants in Africa to evolve away their tusks

A strange phenomenon has gotten the attention of wildlife experts, conservationists, biologists (and hopefully, poachers) around the world.Roughly one-third of the young female elephants in Africa’s Mozambique Gorongosa National Park were born without tusks and developed into adults without them.In a National Geographic report, experts said that poaching was responsible for swaying the hand of evolution in the case of these elephants. "Under poaching pressure, the elephants in Mozambique are evolving tusklessness," the report reads.Elephants without tusks is hardly a new concept — normally, two to four percent of the world’s elephants are tuskless by design. But, the tuskless herd in question are the first generation of elephants born after the state pulled through a 15-year civil war — a war financed largely by trading ivory, National Geographic reported.[caption id="attachment_5541111" align="alignnone" width="1280"]

A herd of African elephants, some of which are tuskless, walking in Addo Elephant National Park in 2009. AFP[/caption]Some estimates report that nearly 90 percent of the area’s elephant population was slaughtered over the course of the war. The survivors were largely tuskless elephants, with little or no ivory to give.Now, these tuskless elephants have mated and grown in number in the area’s elephant population.“The prevalence of tusklessness in Addo is truly remarkable and underscores the fact that high levels of poaching pressure can do more than just remove individuals from a population,” says Ryan Long, a behavioral ecologist at the University of Idaho and a National Geographic Explorer.According to evolutionary biologist Shane Campbell-Staton at the University of California-Los Angeles, whose team studies tusklessness, it remains a mystery how the traits were passed on — genetically speaking. The newfound rise in tuskless elephants is exclusively in females since tusks are an important advantage in male mating practices.

“If this trait was traditionally X-linked—passed down along the X chromosome… which helps determine sex and carries genes for various inherited traits… we would think that because males always get their X chromosome from their mothers, and that you’d have a really large population of males that are tuskless,” Campbell-Staton added.Irrespective of how the spontaneous change came about, the fact that more females in the area have no tusks is a huge advantage for their species’ survival — ivory trade is far from history, still dominant in the black market for exotic animal parts.The phenomenon is a striking example of how pressure on an ecosystem can result in incredible evolutionary adaptations.