 Direct expression of cooperative breeding includes facultative parental care, including alloparenting, and extended post-menopausal lifespan in females, which forms the basis of the Grandmother Hypothesis.Cooperative breeding in humans is theorized as the optimal solution to high energetic costs of survival due to nature of human diet, which involved high-quality foods often in need of processing and cooking.Additionally, food provisioning in cooperate breeding societies may explain the relatively short period of weaning in humans, typically two to three years, when compared to non-human apes who wean their offspring for upwards of six years.