Orangutans live for 30 to 45 years in their natural habitat and can live for up to 50 years in captivity. Females are considered mature and able to reproduce at the age of 10 to 15 years old, while males are between 15 to 20 years old before they are large enough to compete for females.
A female orangutan has a gestational period of eight to nine months. There is usually only one baby born, but it is possible for a female orangutan to deliver twins. According to WWF, the "inter-birth interval can be as low as five years in high-quality habitats." Once the baby orangutan is born, it clings to its mother for up to one year, suckling from her. They continue to suckle until the mother's next pregnancy. Although the weaning period is not over until the young orangutan is 7 to 9 years old, they do leave the mother after the first year, for short periods of time, to explore.
After the weaning period, females often stay with their mothers, while males are chased away from the habitat. At this stage, the young orangutan is considered juvenile and not yet ready to reproduce. They live a semi-solitary life and travel intermittently with other juveniles, as well as with their parents. Males become very solitary when they reach the age of 10 to 14 as a result of not yet being large enough to compete with older males for females with whom to reproduce. Once large enough, they mate with a sexually mature female. This is done for a period of days or even weeks, while they fight off other males and mate frequently with the chosen female. Menopause has been recorded in some captive female orangutans at the age of 48.