The phenomenon affects female elephants and, it has been suggested, could be an adaptation to poaching — but the explanation is probably a different one.
For fifteen years, from 1977 to 1992, Mozambique was the scene of a bloody civil war that ravaged the nation, leaving it in a state of political instability. In addition to the high number of human casualties, vast numbers of elephants also perished in the conflict. The end of hostilities did not, however, bring peace to the pachyderms: poaching is a widespread scourge in Mozambique, partly due to less stringent territorial control compared to other African nations.
In the Niassa National Reserve alone, in the northern part of the country on the border with Tanzania, nearly 11,000 elephants are thought to have been killed since 2011, roughly 70 per cent of the protected area's population, massacred by poachers for their precious tusks. Poachers may, however, find themselves with no tusks left to cut: a recent study, not yet published and announced in National Geographic by Elephant Voices co-founder Joyce Poole, has revealed that the number of female elephants being born without tusks is steadily increasing.
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The research, conducted in Gorongosa National Park, highlighted the intensification of a trend already observed in other areas, one that in this protected area of Mozambique affects nearly one third of females: the generation born after the end of the war in 1992. Thirty-two per cent of the two hundred adult females present in the park have no tusks. Normally, among female African elephants (Loxodonta africana), the absence of tusks affects 2–4 per cent of individuals.
The coincidence between the massive increase in poaching and the "loss" of tusks led researchers to hypothesise that the phenomenon may be a form of evolutionary response by elephants to poachers. "It is possible that poaching has driven an artificial selection of tuskless elephants, which would thus have found a 'trick' for surviving humans," commented Luigi Boitani, zoologist at the Sapienza University of Rome and conservation biology expert. "The hypothesis, however compelling, still needs to be verified: it is equally plausible that the disappearance of tusks is simply a phenomenon of genetic drift, caused by a random change in genetic variability that, in populations this small, may have led to this trait becoming increasingly widespread."
The answer to this question may be simpler, and sadder, than expected, and may lie in genetics itself. It is in fact more likely that the genes for large tusks have been wiped out along with the individuals that carried them. Male elephants with large tusks are the most sought after by poachers; indeed, those known as "tuskers" — males that, owing to a genetic variant, develop enormously sized tusks so long they nearly brush the ground — have all but disappeared.
Whatever the cause of this phenomenon, researchers are trying to understand how the lives of elephants will change with the progressive disappearance and reduction in size of their tusks. Tusks, which are nothing more than elongated upper incisors, are important to these enormous mammals, which use them to drink, dig, strip bark from trees or impress females; but they also matter for ecosystem balance, since many smaller creatures and the health of the habitats elephants frequent depend on the activities of these animals, which are considered a keystone species.