Elephants born without tusks to survive hunting for ivory
Natural selection in real time.
More and more elephants are being born without tusks in Mozambique’s Gorongosa National Park.
And a study just published in Science points out that it is due to an evolutionary response to the brutal slaughter to which these animals were subjected for their ivory during 15 years of civil war.
It is that poaching to obtain tusks financed part of the activities of the two opposing sides and brought the species to the brink of extinction.
Elephant experts working in the park began to notice the phenomenon after the end of the conflict in 1992.
They found that, before the war, about 18.5% of female elephants were born without tusks, and since the end that percentage increased to 33%.
Slaughtered populations
The civil war in Mozambique pitted government forces and anti-communist insurgents between 1977 and 1992.
During the war, 90% of Mozambique’s elephant population was slaughtered by combatants on both sides, to sell ivory and to buy arms and ammunition.
In the same way that we inherit eye color or blood type, genes are responsible for an elephant inheriting the tusks of its parents.
In war, those tuskless elephants were ignored by hunters, making them more likely to pass on those genes to their descendants.
Gen “harml “
Researchers had long suspected that tuskless birth, only seen in female elephants, was linked to gender.
After the genomes of elephants with and without tusks were sequenced, analysis revealed that it was linked to a mutation on the X chromosome that was fatal to males, that they could not develop properly in utero, and that it was dominant in females.
Study co-author Professor Robert Pringle of Princeton University in New Jersey, USA, notes that this discovery may have several long-term effects for the species.
Because this trait is fatal to the offspring of males, it is possible that this means that fewer elephants are born overall.
This would delay the recovery of this species, of which there are about 700 specimens in the national park.
“Being born without fangs might be advantageous during the war, but it comes at a cost,” says Pringle.
Another possible effect is the impact on the landscape, as the study also reveals that elephants with and without tusks eat different plants.
Reversible
However, Pringle emphasizes thatcan be reversible, as populations reboundedon and stop being on the brink of extinction.
“Therefore, we expect this syndrome to decrease, provided that the conservation outlook continues to be as positive as it has been recently,” says the professor.
“There is a huge storm of depressing news about biodiversity, humans and the environment. I think it is also important to emphasize that there are some bright spots ”, he completes.
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