Although co-operative hunting may have played an important role in earlier times, by the Upper Palaeolithic period it became much more highly organized, as bands began preying selectively upon particular preferred species.
Settlement evidence indicates not only that people were occupying new areas and that there were now far greater numbers of people in areas previously inhabited, but also that social groups were often far larger than before.
In some regions, population densities may have risen to the point where there was not enough food and land to go round: in order to resolve potential conflict, it has been suggested that the territories 'owned' by individual groups began to be clearly defined.
Membership of a particular group may have been indicated in particular ways, for example by the way that its members dressed or by the ornaments that they wore: it is certainly at this time that jewellery, made from natural materials such as shells, ivory and animal teeth, appears.
The bodies buried at Sungir', covered with beads that had originally been sewn on clothing, may be uniquely preserved examples of a widespread practice.
Studies of modern hunter-gatherer groups, however, show that a system of well-defined groups and territories was likely to have had considerable built-in flexibility: every member of the group would have kinship ties of some kind with members of other groups, providing the opportunity to shift between groups when circumstances, such as localized food shortages, made this desirable.
Young people were probably exchanged between groups as marriage partners, ensuring both good inter-group relations and a healthy mixing of genes.
