males reach puberty, they show a playful interest in young infants. They will kidnap the infants by luring them away from their harems and inviting them to ride on their backs. This is more often done by "follower" males. This kidnapping can lead to dehydration or starvation for the infant. The harem leader would retrieve the infants from their kidnappers, which is mostly an act to protect their offspring. Thermoregulation Because bipedalism is thought to help reduce thermoregulatory stress, research has investigated how baboons deal with water restriction and thermal loads as quadrupeds. Using implanted data loggers and simulated desert conditions, researchers found baboon internal temperatures increased significantly with water deprivation. When water was given to baboons, their internal temperatures dropped quickly. Therefore, it seems that access to water helps baboons maintain homeothermy and that water restrictions are a major threat to this species. However, baboons can maintain their plasma volume during water deprivation due to an increase in blood colloid osmotic pressure (COP). Hamadryas baboons do this by increasing albumin synthesis. This helps baboons retain fluids when their bodies are experiencing dehydration. In culture Hamadryas baboons often appear in ancient Egyptian art, as they were considered sacred to Thoth, a major and powerful deity with many roles that included being the scribe of the gods. Astennu, attendant to Thoth, is represented as a hamadryas in his roles as recorder of the result of the Weighing of the Heart and as one of the four hamadryas baboons guarding the lake of fire in Duat, the ancient Egyptian underworld. A predynastic precursor to Astennu was Babi, or "Bull of the Baboons", a bloodthirsty god said to eat the entrails of the unrighteous dead. Babi was also said to give the righteous dead continued virility, and to use his penis as the mast of a boat to convey them to the Egyptian paradise. Sometimes, Thoth himself appears in the form of a hamadryas (often shown carrying the moon on his head), as an alternative to his more common representation as an ibis-headed figure. Hapi, one of the Four Sons of Horus that guarded the organs of the deceased in ancient Egyptian religion, is also represented as hamadryas-headed; Hapi protected the lungs, hence the common sculpting of a stone or clay hamadryas head as the lid of the canopic jar that held the lungs and/or represented the protection of the lungs. Hamadryas baboons