Homo neanderthalensis, commonly known as Neanderthals, were a species of early humans that lived in Europe and parts of Asia around 400,000 to 40,000 years ago. They are closely related to modern humans, sharing about 99.7% of their DNA. Neanderthals were adapted to cold climates, with robust bodies and large noses, which helped them breathe in cold air. Neanderthals were skilled hunters and gatherers, using tools made from stone and bone. They are known to have created art and may have practiced burial rituals, indicating a complex social structure. Their extinction is believed to be linked to competition with Homo sapiens and changing environmental conditions.