Science

Ivory Poaching Led to Evolution of Tuskless Elephants

Recent studies have shown African elephants to be genetically born without tusks. Source: Vaughan Leiberum (via Flickr)

By Mia Becker-Hansen | Head of Science and Technology

A study in Gorongosa National Park has found that a previously rare genetic condition in elephants causing them to be born tuskless has become more common, as a consequence of ivory poaching during Mozambique’s civil war.

Genes are responsible for whether elephants inherit tusks from their parents. Tuskless elephants were left alone by poachers due to their lack of ivory, meaning they had a much higher chance of surviving and therefore having offspring, which would also not have tusks.

Elephants with tusks were highly likely to be hunted during the Mozambican civil war from 1977 to 1992. A massive 90% of the African elephant population there were slaughtered by armed forces on both sides for their ivory, which was sold to finance the conflict.

However, this development may not be advantageous to the survival of these magnificent creatures at all. Researchers had long suggested that the trait was only linked to female elephants. Analysis led to the discovery that the trend of tuskless elephants was linked to a mutation in the X chromosome. This meant female elephants could be born without tusks, but the mutation was fatal to males, causing them to not develop properly and die in the womb. Before the war, about 18.5% of female elephants were naturally tuskless. This figure has now risen to 33% among elephants born since the early 1990s.

Professor Robert Pringle of Princeton University noted that as the mutation proves fatal for male elephants, it is possible for fewer elephants to be born overall, slowing the recovery of the population, which now only stands at 700 in the park. Another potential problem is changes to the landscape, as a study has revealed that tusked and tuskless animals eat different plants.

Professor Pringle emphasised that as populations recover from near elimination, the trait should be reversible over time. “We actually expect that this syndrome will decrease in frequency in our study population, provided that the conservation picture continues to stay as positive as it has been recently,” he said. Populations have been growing for two decades and more than tripled since the 1990s.

The whole ordeal reveals the impact that human interference can have on nature. Pringle continued: “What I think this study shows is that it’s more than just numbers. The impacts that people have, we’re literally changing the anatomy of animals.”

Mia Becker-Hansen Science and Technology

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