Early humans lived primarily as nomadic hunter-gatherers in small family bands or groups of 10 to 75 individuals. They subsisted by gathering plants, hunting animals, scavenging, and fishing, adapting their lifestyle closely to their surroundings and climate. Early humans lived in caves or rock shelters and used tools made from stone and bones. They cooked food in stone-lined pits and likely practiced gender and age-based task diversification to increase survival chances, with men mostly hunting and women and children gathering plant foods. Early humans followed seasonal migrations and adapted their diet and shelter to changing climates, using animal hides for warmth and expanding sources of food during warmer periods. Early humans were also social, with evidence of graves showing social status differences. Their lifestyle was flexible and resourceful, involving innovations such as the use of fire for cooking and tool making to thrive rather than merely survive.