Neanderthals were a subspecies of early humans that lived in Europe and western Asia from around 400,000 to 40,000 years ago. They were well-adapted to cold environments, with stocky bodies, barrel chests, and strong limbs that allowed them to store body heat. Neanderthals hunted large game like mammoths and lived in shelters constructed from animal bones. While they were physically robust with large brains, modern humans may have outcompeted Neanderthals for resources. The last Neanderthals disappeared around 25,000 years ago, possibly due to climate change or interbreeding with anatomically modern humans, as DNA evidence confirms some mixing occurred.