Years of poach­ing have spawned new breed of tusk­less ele­phants

National Post (National Edition) - - NEWS - SARAH KNAP­TON

It is a de­vel­op­ment that would have de­lighted Dar­win. African ele­phants are los­ing their tusks in an as­ton­ish­ing ex­am­ple of evo­lu­tion by nat­u­ral se­lec­tion which pro­tects them against ivory poach­ers.

Un­til the ’90s, around 2,500 ele­phants lived in Goron­gosa Na­tional Park in Mozam­bique, but 90 per cent were killed dur­ing the 15-year civil war from 1977 to 1992 — with their ivory used to fi­nance weapons.

Now sci­en­tists have no­ticed nearly one-third of the fe­male ele­phants born since the war have lost their tusks.

Nor­mally, fewer than four per cent of a pop­u­la­tion are born with­out tusks, but be­cause tusk­less an­i­mals were ig­nored by poach­ers, they gained a bi­o­log­i­cal ad­van­tage and were able to mate, and pass on their genes. A team from the Uni­ver­sity of Kent is now car­ry­ing out ge­netic stud­ies to learn more about the new traits.

Do­minique D’Emille Cor­reia Gon­calves, a bi­ol­o­gist from the uni­ver­sity, said: “The elephant pop­u­la­tion to­day is de­rived from most of the ele­phants who sur­vived the war, where they were heav­ily poached for their tusks.

“The key ex­pla­na­tion is that in Goron­gosa Na­tional Park the tusk­less ele­phants were the ones which eluded poach­ing and there­fore passed this trait on to many of their daugh­ters. We could be talk­ing about the re­moval of cer­tain genes from the pop­u­la­tion.”

Even where the ele­phants are born with tusks they are of­ten smaller than usual, again be­cause poach­ers tended to pick out the an­i­mals with most ivory.

Poach­ing has also led to a de­crease in tusk sizes in south­ern Kenya where sur­vivors of a pe­riod of in­tense poach­ing had much smaller tusks, a pat­tern which was re­peated in their off­spring. And in Addo Elephant Na­tional Park in South Africa, 98 per cent of the fe­males are now tusk­less.

Re­searchers in Goron­gosa have also no­ticed the fe­males have de­vel­oped a “cul­ture of ag­gres­sion” and have a low tol­er­ance to ve­hi­cles and peo­ple, likely from a desire to pro­tect their group against poach­ers, but it also could be linked to the lack of tusks, which makes them vul­ner­a­ble. Sci­en­tists are now mon­i­tor­ing the ele­phants by at­tach­ing GPS satel­lite col­lars to 10 fe­males from dif­fer­ent fam­ily units to find out if a lack of tusks af­fects their abil­ity to feed and breed.

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