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Key to ice age extinction found on island in Bahamas

The recent discovery and analysis of ancient fossils in a flooded sinkhole in the Bahamas has shed new light on what caused the ice age extinction.

Recent findings from a flooded sinkhole in the Bahamas suggest that the extinction of ice age animals, such as the woolly mammoth and sabre tooth cat, may have been caused by both climate change and overhunting.

The Pleistocene extinction that occurred roughly 10 to 11 thousand years ago remains one of the great mysteries of the ancient world. The debate over the cause of the extinction centers primarily around human hunting and climate change, but the most recent findings are shedding more light on the matter.

Divers have been exploring a sinkhole on the Abaco Island that up until 2004 remained all but impossible to explore. The once-untouched sinkhole is filled with the poisonous and acidic hydrogen sulfide, but divers have since figured out how to cope with the sulfide.

Now, divers are finding a treasure trove of well-preserved and untouched fossils, and these fossils are shedding light on the ancient past.

The biggest challenge for researchers has been trying to determine whether human activity, primarily hunting, or climate change were the cause of the extinction of the giant beasts that once roamed the Americas. Problem is, humans arrived just as the ice age was ending, making it difficult to separate the two.

Humans didn’t arrive in the Americas until about 10,000 years ago, right as the ice age was coming to an end. In order to cross into the Americas, humans needed to use the Bering land bridge that appeared towards the end of the ice age.

Interestingly, however, humans didn’t arrive in the Bahamas until about 1,000 years ago, long after the ice age extinction. Divers found some 5,000 fossils in the sinkhole, including fossils from 95 different vertebrate animals.

Of those vertebrates, 39 are now extinct on the island, with 17 of the animals having gone extinct during the end of the ice age, and the rest dying off when humans arrived. At least on Abaco Island, humans caused a slightly more serious die-off.

Of course, this alone doesn’t provide enough evidence to suggest that either humans, climate change, or a combination of both were what killed off animals on the mainland. As a smaller, more isolated environment, different conditions were at play.

At the same time, however, the findings do shed light on the Pleistocene extinction, even if the findings are incomplete and limited.

The results were published in the Proceedings of the National Academies of Science.