New discovery: Mammoths took last steps on an isolated Arctic island
Using DNA analysis to catalogue mammoth genomes, scientists have finally discovered where these giants took their last steps before the entire species was wiped out thousands of years ago.
Woolly, tusked mammoths have always inspired curiosity among researchers. The elephant-like mammal weighed as much as a school bus, ate around 400 pounds of plant material each day, and has become a furry symbol of ancient icy weather since the 20th Century Fox hit film, “Ice Age,” sold out movie theatres in 2002.
So it probably comes as no surprise that these enormous mammals spent their final days in the Arctic. An online report in Current Biology, led by Dr. Love Dalén, an associate professor at the Stockholm Swedish Museum of Natural History, suggests the last mammoths to roam the earth lived on an island that split from Russia over 10,000 years ago.
Wrangel Island separated from the continent because of rising sea levels, and with it, one of the world’s last surviving populations of mammoths was isolated.
The report suggests the inbreeding that followed created a population that was unable to sustain itself.
Research highlights
Scientists sequenced the entire genome of two, well-preserved mammoth specimens in the study, “Complete Genomes Reveal Signatures of Demographic and Genetic Declines in the Woolly Mammoth.” Dalén and his team used DNA from the 45,000-year-old soft tissue remains of a woolly mammoth found in northeastern Siberia and a 4,300-year-old tooth from Wrangel Island itself.
Researchers then measured and compared the amount of genetic diversity in each specimen in order to better understand the species’ history and extinction.
“By sequencing the 4,300-year-old, we find it has a 20 percent lower amount of genetic diversity than the older mammoth and a 28-fold higher amount of inbreeding,” Dr. Love Dalén, told Nicholas Bakalar of The New York Times.
Researchers also found the Wrangel Island mammoth’s parents were closely related, another indicator of inbreeding and low genetic diversity.
Mammoths originally declined 300,000 years ago, then intriguingly started to recover around 100,000 years ago.
By the time Wrangel Island separated from Russia, about 12,000 years ago, mammoth populations were declining in numbers once again. “We don’t know why,” Dalen told The New York Times.
But Dalén listed human hunting, environmental disruptions and warming temperatures as possible reasons for the dwindling numbers.
Regardless of what killed them, the research suggests the world’s last mammoths probably died on that small Arctic island – in between the Chukchi Sea and the East Siberian Sea.
Gone for good?
The Harvard Woolly Mammoth Revival Team and a genetic rescue organization called Revive & Restore are working to insert mammoth genes into Asian elephants and make them cold-tolerant. They’re calling it the Woolly Mammoth Revival Project.
And Dalén’s genome sequences could provide the key ingredient to a mammoth restoration recipe.
According to the project website, “The goal is not to make perfect copies of extinct woolly mammoths, but to focus on the mammoth adaptations needed for Asian elephants to live in the cold climate of the tundra.”
Resurrecting mammoths could greatly benefit the Arctic because “Mammoths, like elephants in Africa today, were the engineers of grasslands, keeping trees from growing on the plains and dispersing large amounts of nutrients over immense distances,” the website says.
The return of the famous woolly mammoths, or something similar, could help restore grasslands and in turn help re-establish horse, bison and other grazer populations of the ancient Arctic tundra.
