The first humans were hunter-gatherers. They lived off the hunt and whatever food they found in nature. This is also called foraging. Early humans travelled and foraged for food continuously. They were nomads: instead of living in a fixed home, they travelled from place to place. Learning how to make and control fire made life a little easier for early humans. Fire provided warmth and light, but it was also used to cook meat. In addition, fire scared predators away. Most tools and weapons were made out of wood or stone. The first humans did not know iron or bronze. When a group became too big, it would split up: it was impossible to find enough food for a large group. In an area of 1500 square kilometres , a maximum of two groups could survive. In this way, different tribes were formed that belonged to the same family, but which only rarely met.