They tend to do this when carrying objects in their hands, displaying, or attempting to see over the horizon. An individual chimpanzee belongs to a large main group. However, that group will split up at different times during the day. The size of the social group in which a chimp interacts is always changing. Sometimes a chimp will be in a mixed sex group, a one sex group, alone, or mother infant band.
Chimps are diurnal.
Each main group is very territorial. They have been observed using tools to extract termintes and ants from their nests. They also hunt. Often times they will hunt a juvenile monkey. The chimpanzees hunt in a group, and share the kill with the others.