New scientific research conducted by evolutionary biologists has suggested that the animal kingdom is rapidly evolving as a result of human poaching and hunting. The team looked in particular at African elephants and why so many females are now being born without tusks, a process they say has been triggered by the ivory trade.
Princeton biologists Robert Pringle and Shane Campbell-Staton led the investigation. They found that between 1977 and 2004, the number of female elephants being born without tusks in Gorongosa National Park in Mozambique rose to around 33%. Normally only around 1 in 50 or 2% of elephants are born without tusks.
The scientists believe that because hunting was so endemic in Mozambique elephants with tusks were widely killed while those without tusks were left alive. This then meant that the tuskless elephants went on to breed and create the next generation who were themselves far more likely to carry the tuskless gene.
Elephants being killed for their ivory is sadly commonplace in Africa as their ivory tusks can be sold for hundreds of thousands of dollars. Despite this trade being illegal, a huge black market for ivory still exists.
Pringle and Campbell-Staton back up their evolutionary theory with the fact that the increase in tuskless elephants came at the exact point in the late 1970s when civil war broke out in Mozambique. Armies seeking to get money for weapons killed as many as 90% of the nation's elephant population, causing a huge impact on which animals remained in the gene pool. Between 1972 and 2005, it is thought that 5 tuskless female elephants survived for every 1 tusked elephant.
What is perhaps surprising is the tuskless trait has been passed on only to female elephants, the males remain fully tusked despite being also attacked and killed. The research team believes the tuskless gene, known as AMELX is only passed on by mothers on the X chromosome and that this is why male elephants remain in their original state.
While tusklessness may save the elephant's lives, it could have an impact on their societies and the wider eco-system.
Campbell-Staton says:
"Tusks are multi-purpose tools to strip bark from trees, dig up valuable minerals, or uncover subterranean water sources. If you don't have your tusks, your behavior shifts – you're no longer pushing trees over because you can't strip their bark."
He adds:
"This is an example of how human activity is changing the evolutionary trajectory of species all across the tree of life… humans are the most influential evolutionary pressure in history besides the five major mass extinction events."
[Based on reporting by: science alert]
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