Every year, when the thaw arrives in Siberia, groups of explorers set out in search of the mammoth. Tusks and other bones from these extinct pachyderms surface so frequently that locals use them to prop up their tents or sell them on the black market. In the best-case scenario, those who find some of these carcasses are scientists, leading to extraordinary discoveries about the vanished fauna of the Ice Age.
The researchers focused on the Basin of Mexico, which is well south of where any woolly mammoths were likely to be found. To begin with, there were a lot of bones. The Basin of Mexico has been heavily built up over the centuries, and a lot of mammoth remains have been discovered, including over 100 individuals during the construction of Mexico City's international airport.