Just like the giraffes that acquired long necks in Lamarck’s theory, elephants are evolving to go tuskless as a way to escape being poached. In a report titled ‘Ivory poaching and the rapid evolution of tusklessness in African elephants’ published in Science magazine, scientists examined the impacts of ivory poaching during the Mozambican Civil War (1977 to 1992) on the evolution of African savanna elephants (Loxodonta africana) in Gorongosa National Park. “In response to heavy poaching by armed forces, African elephant populations in Gorongosa National Park declined by 90%. As the population recovered after the war, a relatively large proportion of females were born tuskless," said the study. Talking about the same issue, a report in Nature said: “Before the war, about 18.5% of females were naturally tuskless — a trait that made them undesirable to poachers. Among the 91 female elephants that have been born since the war, the researchers show, that fraction has risen to 33%." However, the tuskless trait is fatal for male elephants. So, it’s yet to be seen how long would this trait be passed on.
“In the study, Campbell-Staton and his colleagues noted that tusklessness is seen only in female elephants. This, and the pattern of inheritance of the trait, suggested that it is caused by a mutation on the X chromosome that is fatal to males and dominant in females — just one copy of a mutation is needed to cause it. The researchers searched through the elephants’ genomes looking for regions on the X chromosome that differed between those with and without tusks, and showed signs of recent selection pressure," added the report in Nature.
The selective killing of species that bear anatomical features such as tusks and horns is the basis of a multibillion-dollar illicit wildlife trade that poses an immediate threat to the survival of ecologically important megafauna worldwide, said the study in Science. Megaherbivores are especially vulnerable to overharvesting because of their large habitat requirements, small population sizes and long generation times.
The Mozambican Civil War was fought between Front for the Liberation of Mozambique and anti-communist Mozambican National Resistance. Both parties funded their sides by hunting elephants for their ivory.
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