Vegetation Change Wiped Out Ice Age Beasts Like Woolly Mammoths

A new study has revealed that it wasn't just climate change that killed off the woolly mammoth. Instead, the changing diet of woolly mammoths, woolly rhinoceros and other animals of the arctic was the main driver behind their extinction. Eske Willerslev and his research team at the University of Copenhagen have determined this theory through DNA analysis.

The new analysis offers an additional theory alongside the already accepted climate warming, prehistoric hunter and comet impact theories for the cause of this mass extinction. The study was published in Nature journal where the researchers analyzed new DNA of arctic vegetation over the past 50,000 years.

They found that 10,000 years ago the woody plants known as forbs, which included sagebrush, yarrow, mums and tansies, disappeared from the Arctic steppes. They were replaced by grasses that spread across the polar regions. These grasses were previously believed to be a formidable substance for the mammoths to survive on. However, that claim was refuted in this study.

By sampling permafrost cores from 50,000 years ago in 17 locations that included northern Russia, Canada and Alaska, the team was able to determine that forbs once dominated the Arctic steppes. More importantly, the mammoths, rhinos, horses, reindeer and elk relied on these plants as a food source. The researchers also examined 18 preserved samples of stomach contents and scat from these animals and saw that forbs were a large part of their diet.

The warming climate is what ultimately contributed to the disappearance of the forbs. The wetter environment that resulted from the ending of the Ice Age seemed to favor the grasses over the forbs. Willerslev believes that previous research did not pay enough attention to this factor, which also found that forbs were a great source of protein and easier to digest than grass. Overall, the vegetation change in the Arctic that resulted in shrubs, grasses and mossy tundra was most likely a key factor in the extinction of the megafauna that roamed the Earth during the Ice Age.

To read more about this study, visit this National Geographic article.