New research suggests that woolly mammoths and humans may have lived alongside one another in what is now modern-day New England. As reported in the journal Boreas, scientists have used carbon-dating to work out how old the famous Mount Holly mammoth fossil actually is. It turns out, it was roaming Northeast America 12,800 years ago, roughly around the time that humans arrived in the region.

The fossils were discovered in 1848, in a peat bog near Mount Holly in Vermont as railroad lines were being constructed. Two tusks, a molar, and many bones were found and then shared among different collections. A rib fragment became part of the Hood Museum of Art in Hanover, New Hampshire and this is what the researchers used to learn more about this sample of America's lost megafauna.

"It has long been thought that megafauna and humans in New England did not overlap in time and space and that it was probably ultimately environmental change that led to the extinction of these animals in the region but our research provides some of the first evidence that they may have actually co-existed," co-author Dr Nathaniel Kitchel from Dartmouth College said in a statement.

The researchers extracted about 1 gram of material from the rib and analyzed it to estimate isotopic concentration. Each chemical element come in different isotopes. They have the same chemical properties but have a different number of neutrons in their cores. A lot of these isotopes are slightly radioactive, and over time decay, turning into stable isotopes, which are not.

By comparing the ratios of these isotopes scientists can learn a lot, including how long ago something died based on its concentration of carbon-14 and its stage of decay (hence carbon dating). They can also get hints about diet using nitrogen. While the carbon result is certainly vital to understand when the mammoth died, the nitrogen is also very valuable, potentially helping us understand why these animals died out.

Kitchel and co-author Jeremy DeSilva found the Mount Holly mammoth had the lowest nitrogen value of any mammoths found in Northeast America and is among the lowest recorded for these animals worldwide. It suggests that these animals had to eat alder or lichens during the last glacial period, when the landscape was denser due to climate warming.

Humans' interactions with woolly mammoths in the American Midwest have been extensively covered but this is the first tentative evidence that this might have happened on the eastern side of the continent. The argument about whether mammoths and other megafauna went extinct due to overhunting or climate change has long been raging. Previous research has suggested that humans hunted and buried mammoths in peat bogs to preserve their meat, but there's little evidence that early humans in New England did this. 

"The Mount Holly mammoth was one of the last known occurring mammoths in the Northeast," said DeSilva. "While our findings show that there was a temporal overlap between mammoths and humans, this doesn't necessarily mean that people saw these animals or had anything to do with their death but it raises the possibility now that maybe they did."