Fig. 2: Faunal collagen δ³⁴S values from Eurasia through the Late Pleistocene and Holocene.

Each data point represents a single animal specimen, which has been directly radiocarbon dated. a, The North Greenland Ice Core Project (NGRIP) oxygen isotope record⁴², a proxy for global temperature. b, Faunal collagen δ³⁴S values. Shaded blue area indicates approximate duration of the LGM. The dashed purple lines indicate approximate timing of continuous permafrost development (about 30 kyr bp) and thaw (about 15 kyr bp) in western Eurasia. Pink squares: samples collected from regions where no permafrost was present during the last 50,000 years. Green circles: samples collected from areas that either had permafrost present at the LGM or were under ice sheets/glaciers at the LGM but where permafrost/ice is absent today. Yellow triangles: samples collected from regions in which permafrost has been present throughout the past 50,000 years.