This article investigates how in the Soviet Arctic researchers and indigenous communities searched and understood the mammoth before and during the Cold War. Based on a vast number of published and unpublished sources as well as interviews with scholars and reindeer herders, this article demonstrates that the mammoth, as a paleontological find fusing together features of extinct and extant species, plays an in-between role among various environmental epistemologies. The author refers to moments of interactions among these different actors as “environmental encounters”, which comprise and engage with the physical, political, social and cultural environments of the Arctic. These encounters shape the temporal stabilisations of knowledge which enable the mammoth to live its post-extinct life. This article combines approaches from environmental history and anthropology, history of science and indigenous studies showing the social vitality of a “fossil object”.