Niche Animal Homes • Earth.com

Further research revealed the tunnels to be palaeoburrows — which surprised the archaeologists. “I didn’t know there was such a thing as palaeoburrows,” Heinrich said. “I’m a geologist, a professor, and I’d never even heard of them.” Since he authored a massive study on them, he’s probably familiar now. Photo Credit: Ted Spiegel/CORBIS/Corbis via Getty Images

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