Puberty in both sexes occurs at about seven years, but males are not fully integrated into the social hierarchy until 15 or so. Females raised in captivity begin mating at eight to nine years and give birth for the first time at 10-11 years old. Wild females mature three to four years later. There is no breeding season. Chimpanzee females are not receptive for three to four years after giving birth, then resume sexual activities for one to six months until conception.
Females mate only when in heat.
For the first week or more, female chimps are promiscuous and mate on an average of six times a day. Toward the last week of estrus, when ovulation occurs, high ranking males may compete for mating rights. Reproductive capability in the female may last at least until the age of 40. Maximum life span in the wild may be 60 years. The newborn is helpless with only a weak grasping reflex and needs support from the mother's hand during travel.