“Throughout history, humans have threatened the survival of elephants. Poaching has killed staggering numbers of these powerful mammals.”
“In Mozambique’s Gorongosa National Park the elephant population was nearly wiped out completely. Only a rare natural trait seems to have saved a small number, tusklessness. Yet this evolutionary development could come at a high cost.”
“In central Mozambique conservationists have been closely observing the elephants of Gorongosa National Park. Fifty years ago around 2500 of these African giants roamed this area. But from 1977 to 1992 Mozambique was plunged into a civil war, a human conflict that also killed around 90% of Gorongosa’s elephants.”
“Thanks to conservation efforts over the past two decades numbers are on the up again. Today the park is home to approximately 800 elephants. But researchers monitoring them have noticed an unusual trend. Many of the females are lacking tusks.”
“African elephants are occasionally tuskless. It is a trait that occurs naturally in around two to four percent of the female population.”
“In Gorongosa, before the war, the proportion was a bit higher than average, 18.5% of the park’s female elephants were tuskless. But of those that survived the years of conflict 51% were tuskless and 33% of those born after the war were also lacking tusks.”
“According to conservationists and evolutionary biologists what we are witnessing here is natural selection in action. The impact of human conflict has literally changed how these elephants look.”
“During Mozambique’s civil war the need for money to finance the conflict made the demand for elephant tusks skyrocket.”
“Ivory is one of the most prized materials in the world, historically fetching incredibly high sums on the global market. At its absolute peak in 2014 it was sold for around $2100.00 US dollars per kilo in Asia where demand was highest.”
“But even back in the 1970s and 80s the international ivory trade was flourishing. In Kenya, uncarved ivory was worth around $200.00 per kilo in 1989, around 36 times what it had been worth 20 years previously. For poachers it was a lucrative business, and a bloody one, too.”
“Elephants tusks are embedded roughly a third of the way into their skulls so extracting them is brutal.”
“From 1979 to 1989 around half the total population of African elephants was killed. During the 15 years of conflict in Mozambique more than 2000 elephants were poached in Gorongosa, only around 10% remained. And perhaps, unsurprisingly, just over 50% of the survivors were tuskless.”
“This rare inherited trait had made them less interesting to poachers. Not having tusks turned out to be life-saving.”
“The extremely high rate of poaching in Gorongosa effectively resulted in a form of natural selection. With the tuskless gene stronger in the reduced elephant population the chances of it being passed on were higher.”
“But scientists wanted to find out how the trait was inherited and why it only seemed to be present in females. A team of evolutionary biologists lead by Shane Campbell-Staton has been investigating the genetics of tusklessness. Their research is astonishing.”
“Looking at the roughly 300 genes involved in human tooth development the team managed to find similar genes in elephants. Comparing blood samples from animals with and without tusks showed differences in DNA sequences.”
“Eventually they narrowed it down to a couple of possible genes. This genetic mutation only ever occurs in females. It is passed down along the x chromosome and is usually lethal to males which explains why in herds like the ones in Gorongosa no tuskless males have been found.”
“In the case of these African elephants tusklessness could be seen as a biological advantage. Put simply, it prevented them from being killed.”
“But tusks are also vital to elephant survival. They are used for many essential activities; digging for water, stripping food from trees, lifting objects, competing for mates and even self defense. Life without them is harder.”
“Scientists working in Gorongosa have fitted a group of tusked and tuskless elephants with gps collars hoping to learn how tusklessness might affect their behavior.”
“Already they are seeing signs that the elephant’s diets may be significantly different. Those without tusks might choose bark and leaves that are easier to strip which could have a big impact on local plant life.”
“Elephants are a keystone species meaning that they sculpt and maintain their environment.”
“Changes in behavior and population numbers can have knock-on effects on other animals and vegetation. Whole eco-systems across Africa could be changed if the tuskless trend continues.”
“And what is more, the fact that tusklessness is fatal to males could have an effect on population growth. Scientists suggest that fewer elephants might be born overall which would negatively impact the species recovery in areas already badly affected by poaching.”
“Evolution is not just something that happened millions of years ago but an ongoing process. The increased rate of tusklessness in Gorongosa’s elephants is just one example.”
Source (1)
“But while in the short term this trait may have saved elephant’s lives by making them less attractive to poachers we must not let ourselves think of it as a good thing. In the long term tusklessness is a sign of a worrying development.”
“Humans are becoming an increasingly strong driver in evolution and our actions can have a lasting impact on the very face of wildlife.”
“Keep watching for more fascinating videos about elephants and if you want to learn more about Gorongosa National Park and its elephant ecology project check out the link (2) …”
Donate to Gorongosa’s Elephant Ecology Project (2)
Sources:
(1) ‘How not growing tusks saved elephants’ lives’ creative commons video by Terra Mater
https://www.youtube.com/ watch?v=_O6gWnBYkXc
(2) Gorongosa Elephant Ecology Project https://gorongosa.org/elephant-ecology-project/
Images & transcribed from: creative commons video by Terra Mater ‘How not growing tusks saved elephants’ lives’ (1)
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