Trade

Non-reciprocal exchanges of goods and services (i.e., one kind of good or service for another) occur among all or very nearly all peoples. Trade occurs between individuals and between groups. There is widespread evidence of trade, often over considerable distances, for many millennia. Even among hunters and gatherers trading patterns may be elaborate. Some forms of trade have pronounced ritual, ceremonial, or ritual functions rather than more narrowly economic functions; these ritualized forms are often described as gift exchanges. Reciprocal exchange of services - such as grooming or assistance in conflict - is common among primates and other species. It is the inclusion of goods, exchanges between groups, and long-distance exchange that distinguishes human trade. The exchange of food for sex occurs in various species. Trade may have its roots in exchanges among primates, with those behaviors being extended to the numerous products of human activity at some point in hominin ancestry.