A tuft of hair from an extinct Ice Age woolly mammoth, recovered from the permafrost of Siberia’s Yakutia region.

Woolly mammoths possessed exceptionally thick, coarse fur that insulated them against extreme cold. Their coat was composed of long, protective guard hairs and a dense, shorter undercoat. The undercoat was seasonally shed from spring through autumn, helping regulate body temperature as conditions changed.

Rising global temperatures are causing underground permafrost to thaw, leading to the exposure of well-preserved natural specimens from the Ice Age.