Gigantopithecus
Gigantopithecus (from the Ancient Greek ' "giant", and ' "ape") is an extinct genus of ape that existed from perhaps nine million years to as recently as one hundred thousand years ago, at the same period as "Homo erectus" would have been dispersed, in what is now India, Vietnam, China and Indonesia placing "Gigantopithecus" in the same time frame and geographical location as several hominin species. The primate fossil record suggests that the species "Gigantopithecus blacki" were the largest known primates that ever lived, standing up to and weighing as much as , although some argue that it is more likely that they were much smaller, at roughly in height and in weight.
Sexual dimorphism in non-human primates
Extant primates exhibit a broad range of variation in sexual size dimorphism (SSD), or sexual divergence in body size. It ranges from species such as gibbons and strepsirrhines (including Madagascar's lemurs) in which males and females have almost the same body sizes to species such as chimpanzees and bonobos in which males’ body sizes are larger than females’ body sizes. In extreme cases, males have body sizes that are almost twice as large as those of females, as in some species including gorillas, orangutans, mandrills, hamadryas baboons, and proboscis monkeys.
Patterns of size dimorphism exhibited in primates may correspond to the intensity of competition between members of the same sex for access to mates–intrasexual competition, counteracted by fecundity selection on the other sex. Some callitrichine and strepsirrhine primates are, however, characterized by the reverse dimorphism, a phenomenon in which females are larger than males. For lemurs, for example, females’ dominance over males accounts for the reverse dimorphism.