A hunting-and-gathering society is a preindustrial society in which people rely on whatever foods (such as wild fruits, vegetables, nuts, and hunted animals) and fiber are readily available in their natural environment in order to live and sustain themselves. These societies typically have a nomadic or semi-nomadic lifestyle, moving from place to place in search of food and resources as they become seasonally available. They generally have a small population size and a relatively simple social structure with a minimal division of labor, often based on age and sex. Hunting-and-gathering was the primary mode of subsistence for humans throughout most of history, and some relatively isolated groups continue to practice this way of life today. Their survival depends on their knowledge of the local environment and their skills in hunting, fishing, and gathering wild plants.