Ancient Arctic mammals: Tiny teeth reveal polar region as cradle of evolution

Newly discovered ancient mammal teeth from Alaska suggest the Arctic was a significant center for mammalian evolution. The fossils, belonging to three new rodent-like species, indicate mammals adapted and diversified in polar environments around 73 million years ago, challenging the idea of the Arctic as a lifeless edge. These findings reveal the ancient Arctic was a dynamic biome and a crucial corridor for intercontinental migration, contributing to the deep history of mammalian evolution.