Ancient Lystrosaurus tusks may show the oldest signs of a hibernation-like state
These oddball ancestors of mammals might have slowed down to wait out the polar darkness
![illustration on an ancient Lystrosaurus](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2020/09/090420_SM_torpor_feat.jpg?fit=1028%2C579&ssl=1)
Tusks from ancient Lystrosaurus animals (one shown in this artist’s reconstruction) have dark bands that might signal periods when the animals wintered in a state akin to hibernation.
Crystal Shin