University of Idaho professor part of team studying tuskless elephants

October 22, 2021 4:33 PM

Tasha Cain-Gray,

Posted: October 22, 2021 4:33 PM

by Tasha Cain-Gray

MOSCOW, Idaho — An associate professor at the Univerity of Idaho is working on research that could help explain why some African elephants are evolving without tusks.

The university said Ryan Long, an associate professor of wildlife sciences there, and his colleagues found the reason might have to do with widespread poaching.

The study, called, “Ivory poaching and the rapid evolution of tusklessness in African elephants” was published Friday in the journal Science, looks into the effect people have had on elephants. One of the biggest impacts humans have had is poaching the animals for their white tusks.

Until recently, there was nothing directly linking poaching to the tuskless phenomenon. However, now, the researchers found there could be two genes associated with mammal tooth development in play when it comes to female elephants being born without tusks. One of them is connected to the X chromosome and is deadly to male elephants, wildlife experts said.

The researchers said they “had a hunch that the tuskless phenotype was passed down in the X chromosome.” So, they collected data and blood samples from elephants in the Gorongosa National Park in Mozambique to “confirm their suspicions.”

So, how did we get here?

The research paper goes into the history of the Mozambican Civil War, which lasted from 1977 to 1992. During that time, 90 percent of elephant populations were wiped out by people who sold their ivory tusks to pay for the war, the researchers said.

Elephants that didn’t have tusks at the time were not killed. So, they reproduced at higher numbers than the ones that had tusks and passed along the tuskless trait.

That leads to more elephants in Mozambique’s Gorongosa National Park being more likely to not have tusks.

“We evaluated the impacts of intense ivory poaching during the Mozambican Civil War on the evolution of African elephants,” Long said. “We found that the frequency of tusklessness among adult females after the war was significantly higher than before the war and was much greater than expected in the absence of selection for tusklessness, suggesting an evolutionary response to poaching.”

Because tusks are a defining feature of elephants and used for a variety of behaviors – including digging for water and stripping bark from trees – how the elephants adapt without them, and how that affects the ecosystem, is still unresolved, Long said.

You can find the entire published study here.