The fur of the Arctic fox provides the best insulation of any mammal and its thickness increases by 140% during winter.
Apparenly they do not start to shiver until the temperature drops to −70 °C (−94 °F).
https://video.nostr.build/51ff5b1896e1f4ab40d7b1e9d52dbe4123329bdcf036fdc2d3a5d8ce074c6519.mp4
