A research team from the National Parks Service and Bugbee's Mammoth Site of Hot Springs, S.D., working on the Channel Islands off the coast of California, discovered an intact – and surprisingly small – mammoth skull that they say offers clues both to the evolution of the Ice Age mammal and human migration into North America.
The US Geological Survey analyzed a charcoal sample found near the skull and dated it to 13,000 years old, which places the mammoth and the Arlington man, thought to be the oldest human remains in North America, on the same island at the same time.
“This mammoth find is extremely rare and of high scientific importance. It appears to have been on the Channel Islands at the nearly same time as humans,” said paleontologist Justin Wilkins in a statement. “I have seen a lot of mammoth skulls, and this is one of the best preserved I have ever seen.”
Elsewhere in the world, researchers have long known that human and mammoths coexisted and that humans hunted the giant mammals. In January, researchers in Siberia discovered 45,000-year-old mammoth remains with distinctive marks indicating that it had been killed by a hunter – once again tracking human migration through mammoths.
"There's a possibility the mammoths died out before humans arrived, and it's possible humans caused their extinction, hunted them to extinction," geologist Daniel Muhs of the US Geological Survey told CNN.
"But there's a third possibility that at the end of the last glacial period, mammoths could have been under stress with limited food resources with sea levels rising at the islands," he says. "Then the arrival of humans delivered the final blow."
A debate over whether humans caused the mammoths' extinction has been raging throughout the scientific community for years, and another finding of the two species in close proximity will only fuel the fire.
But separate from that debate, the discovery of the skull may shed new light on mammoth evolution. Despite its remarkably preservation, scientists were not able to classify the skull, being too large for a pygmy mammoth and too small for a Columbian mammoth.
The 14-foot Columbian mammoth migrated to North America 1.5 million years ago, and then to the Channel Islands during the past two ice ages. After the ice age ended, rising seas isolated the island population, which evolved into the 6-foot pygmy mammoth.
"This [skull discovery] opens the possibility that this mammoth was intermediate in size between the two species," Monica Bugbee, a member of the project, told CNN. "It could represent a transitional animal, somewhere on the way to becoming a completely dwarfed pygmy mammoth."