Within the community, these groups are quite fluid, with adults wandering off and joining other groups. Mother chimps will often form attachments with offspring and stay with them as a group. Between communities, there is a lot of hostility. Chimpanzees spend a lot of time grooming each other. This strengthens their social bond.
Chimpanzees communicate vocally, with facial expressions, and with gestures.
Females give birth to a single young chimp after about 8 months. Young chimpanzees are born helpless and spend the first 6 months clinging to the hair on its mother's chest while she is in motion. From 6 months to 2 years, young chimpanzees ride on the mother's back. They are weaned at 5 years. Young chimpanzees will often stay with their mothers for many years, thus forming a subgroup within the community.