Posted on 10/22/2021 8:28:16 AM PDT by Red Badger
Shane Campbell-Staton, an evolutionary biologist at Princeton University, spent most of his career researching lizards.
But at 3:00 am one morning in 2016, he was browsing YouTube and came across a video about African elephants. It described a bizarre trend: Many female elephants in Mozambique's Gorongosa National Park lacked tusks.
That was unusual, since usually just 2 percent of female African elephants are tuskless. Intrigued, Staton-Campbell reached out to colleagues who researched elephants, but found no one had looked into the mystery.
But Princeton biologist Robert Pringle invited him to the park to study the phenomenon himself.
"It took me 1.5 seconds to say, 'Yea I'll definitely do that,'" Staton-Campbell told Insider.
Seven months after watching that video, he found himself in a helicopter, counting elephants. After comparing current populations to historical video footage from Gorongosa park, he and Pringle came to a disturbing conclusion: The number of tuskless females had increased dramatically over about three decades.
Between 1977 and 2004, the proportion of females who lacked tusks jumped from 18.5 percent to 33 percent.
The results of their research were published Thursday in the journal Science.
Victims of a civil war The start of the trend away from tusks is no coincidence, the new study says.
Mozambique entered a bloody civil war in 1977. Armies on both sides hunted African elephants for their tusks, selling the ivory to finance war efforts over 15 years. By 1992, the elephant population in Gorongosa had declined by more than 90 percent.
During the war, the frequency of tuskless females in the park almost tripled, to the point where one in every two females lacked tusks.
Given that poachers targeted tusked elephants, it made sense that the animals' rare tuskless counterparts had a greater chance of survival.
That advantage persisted even once the civil war ended, though the proportion of tuskless females being born did go down somewhat. Between 1995 and 2004, one in every three females born in the park were tuskless, compared to about one in every five born before the war.
Overall between 1972 and 2000, the researchers calculated, five tuskless females survived for every one tusked female.
That suggested to Campbell-Staton's group that poaching had driven a rapid evolution.
"It's extremely, extremely improbable to get that magnitude of change just from chance alone," he said.
A lethal trait for males The researchers were puzzled, however, as to why tusklessness was a trait limited to females.
Even in areas with large African elephant populations outside of Gorongosa park, there are only scattered anecdotes of tuskless males. That pattern suggests a genetic origin for tusklessness that is linked to an elephant's sex.
After sequencing the genomes of both tusked and tuskless females in the park, the researchers identified a dominant gene that could be responsible for tusklessness, called AMELX.
AMELX gets passed from mothers to their offspring on the X chromosome, and humans have the gene, too. In people, the disruption of that gene causes brittle teeth and diminishes tooth growth in females, Campbell-Staton said. But if a human male inherits a disrupted AMELX gene on his X chromosome, he usually dies.
The study authors think it could be the same with African elephants: If a male elephant inherits a disrupted AMELX gene, he dies; but the mutated gene would only result in tusklessness in a female elephant.
The loss of tusks could create ripples through entire ecosystems Tusklessness might seem like a non-critical issue, Campbell-Staton said, but the trend could impact African elephants' whole ecosystems.
"Tusks are multi-purpose tools to strip bark from trees, dig up valuable minerals, or uncover subterranean water sources," he said. "If you don't have your tusks, your behavior shifts – you're no longer pushing trees over because you can't strip their bark."
Other animals in the African savanna are dependent on those elephant behaviors. When elephants push over trees, that creates new space for other grassland plants, which in turn create habitats for other species. A decline in tusked elephants hampers that process.
"This is an example of how human activity is changing the evolutionary trajectory of species all across the tree of life," Campbell-Staton said, adding, "humans are the most influential evolutionary pressure in history besides the five major mass extinction events."
Although Mozambique's civil war is long over, it may take a century for the proportion of tuskless females to drop back to pre-war levels.
"It'll probably take five, six, or seven generations to get back to the 2 percent that you would expect absent any poaching pressure," Campbell-Staton said.
That, of course, is far longer than the one generation that "it took to mess it up," he added.
This is like the peppered moth phenomenon. It’s not that the evolved. What happened was that the makeup of the population evolved, as what has happened to the human population of north amereica since the white man first set foot here.
Blacks make up a much larger part of the population of the US than in 1500, and native americans make up a much smaller percentage. But nobody evolved. Rather, the population stats evolved.
Will we quickly evolve into having a new obnoxious filtering device in our visage?
I guess we’ll find out if having tusks is a necessary survival trait. It appears not to be.
Elephants use their tusks for digging and protection..................
Oh, did the brady bunch get assault tusks banned and we missed it?
Evolution is selective breeding on very long time scales. There is some reference in the Bible to what is a day to man vs what is a day to God. Evolution is not anti God.
You don’t assume to know the mind of God do you?
:-)
Eisenstein even said: “God does not play dice with the universe”
What do we know. We haven’t got a clue about gravity or that mysterious force, dark matter or energy or whatever you want to call it.
All I know is you can see God in a Narwhals tusk.
Will we quickly evolve into having a new obnoxious filtering device in our visage?
Only if they start shooting the ones who don’t
I don’t assume to know the mind of God....
But this isn’t evolution, it is human induced selective breeding by criminals................
Oh, “THE PURGE”. Those unclean, unpatriotic, unvaxxed stoopid bast**ds. Right brandon?
I would’ve expect the market value for Ivory to be rather low right now. Most of the industrial uses are likely to have synthetic substitutes that cost a lot less.
Ivory has historically been used for piano and organ keys, billard balls and furniture handles. There is some electrical equipment that also uses Ivory.
I’m thinking it is mostly instrinsic value that keep Ivory viewed as something ‘precious’.
If I was more serious about learning to play the piano, I would learn even while using keys made of acryllic.
Time to leave the remaining tusked elephants alone.
Between 1977 and 2004, the proportion of females who lacked tusks jumped from 18.5 percent to 33 percent.
IOW, artificial selection. Melanism in squirrels is a recessive trait, but when they live and breed in a protected area, such as a college campus, there is a noticeable increase in the number of black squirrels, and that leads to a universal or near-universal survival of the recessive trait.
Thanks Red Badger.
And a noticeable increase in squirrel on squirrel crime................
Over the years I have posted that we should just tranq gun every elephant and rhino and remove their tusks, sell the ivory on the open market and use the money to ... protect such animals.
The criticism is usually sumthin like “somehow they need those tusks” but a guy with an AK47 is gonna give far more protection to the animal than the tusks.
Now, nature is having its own say in this controversy.
ICWUDT, melanist
tuskless elephants
lots of them in congress
Losing a body part is not evolution. It is devolution.
It’s BS!
Is nobody teaching the famous study where the scientist cut the tails off rats for multiple generations over years and... NONE of them produced tailless rats?!
It’s selective breeding which the world has known about since farming began and we domesticated wolves and cats!
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.
