Desperation, Survival, Evolution & Elephant Tusks

  

I’ve traveled to the sub-Sahara, mostly in eastern and southern Africa, several times since the late 1970s. Every time I have gone back, there are fewer wild animals, more people and no shortage of poachers or conflicts. Cheetah were decimated by disease, but rhino and elephant were slaughtered by poachers or decimated in regional wars. Rhino for their precious horns used in Arab and Indian ceremonial dagger handles and as purported aphrodisiacs to the Chinese. Elephant for the valuable ivory tusks. It is sad compounded on sad. Watching elephant pay homage for dead former herd members, caressing their bones with extreme reverence, is an unforgettable sight. Seeing a full-time armed guard standing by a white rhino (now virtually extinct) is heartbreaking.

Nature seems to have stepped in with possible evolutionary solutions in some pockets where combat killed an ungodly number of animals, particularly elephant. Christina Larson, writing for the October 3rd Associated Press, examines the post-war evolutionary change in female elephant in Gorongosa National Park, Mozambique: “A hefty set of tusks is usually an advantage for elephants, allowing them to dig for water, strip bark for food and joust with other elephants. But during episodes of intense ivory poaching, those big incisors become a liability… Now researchers have pinpointed how years of civil war and poaching in Mozambique have led to a greater proportion of elephants that will never develop tusks.

“During the conflict from 1977 to 1992, fighters on both sides slaughtered elephants for ivory to finance war efforts. In the region that’s now Gorongosa National Park, around 90% of the elephants were killed… The survivors were likely to share a key characteristic: Half the females were naturally tuskless — they simply never developed tusks — while before the war, less than a fifth lacked tusks.

“As with eye color in humans, genes are responsible for whether elephants inherit tusks from their parents. Although tusklessness was once rare in African savannah elephants, it’s become more common — like a rare eye color becoming widespread.

“After the war, those tuskless surviving females passed on their genes with expected, as well as surprising, results. About half their daughters were tuskless. More perplexing, two-thirds of their offspring were female… The years of unrest ‘changed the trajectory of evolution in that population,’ said evolutionary biologist Shane Campbell-Staton, based at Princeton University…

“Researchers in Mozambique, including biologists Dominique Goncalves and Joyce Poole, observed the national park ’s roughly 800 elephants over several years to create a catalog of mothers and offspring… ‘Female calves stay by their mothers, and so do males up to a certain age,’ said Poole, who is scientific director and co-founder of the nonprofit ElephantVoices.

“Poole had previously seen other cases of elephant populations with a disproportionately large number of tuskless females after intense poaching, including in Uganda, Tanzania and Kenya… ‘I’ve been puzzling over why it’s the females who are tuskless for a very long time,’ said Poole, who is a co-author of the study…

“Most people think of evolution as something that proceeds slowly, but humans can hit the accelerator… ‘When we think about natural selection, we think about it happening over hundreds, or thousands, of years,’ said Samuel Wasser, a conservation biologist at the University of Washington, who was not involved in the research. ‘The fact that this dramatic selection for tusklessness happened over 15 years is one of the most astonishing findings.’

“Now the scientists are studying what more tuskless elephants means for the species and its savannah environment. Their preliminary analysis of fecal samples suggests the Gorongosa elephants are shifting their diet, without long incisors to peel bark from trees… ‘The tuskless females ate mostly grass, whereas the tusked animals ate more legumes and tough woody plants,’ said Robert Pringle, a co-author and biologist at Princeton University. ‘These changes will last for at least multiple elephant generations.’” The genetic differences are measurable.

Mankind’s devastation of this planet is staggering. The human population has pushed Malthusian limits… with at least double the scientifically sustainable number of people that the earth can hold. We tend to focus on climate change at the exclusion of so many other human excesses that are rewriting nature. But can nature fight back enough to save the planet and most of species on it?

I’m Peter Dekom, and as we kill off wildlife and productive land, are we also killing ourselves in a self-indulgent feast of earth’s dwindling resources?