Skeleton of Baboon - Papio spp.
The baboons are a genus of old-world monkeys (meaning that they’re larger primates from Asia and Africa with non-prehensile tails) that exist in matrilineal troops (the females stay with their mothers, the males join another troop).
They’re fascinating creatures. The color varies from red to blue to pink, but all baboons have a rough, hairless, nerveless pad of protruding tissue on their bum, called ischial callosities. The primary function of these pads is similar to our own bums - sitting! Baboons sit like humans more than any other primate.
In females, their ischial callosities swell when they’re in estrous and ready to mate. During breeding season, the female baboons will present their swollen rumps to males, as a signal that she wants to mate.
Young baboons nurse for about a year, and during this time, when major fights break out in troops (baboon groups), male baboons have been seen taking nursing or just-weaned youth hostage, in order to avoid being hurt, themselves.
Despite their generally-herbivorous diet, baboons are some of the more hostile primates, and their over-sized canines scare off many predators of animals their size. Humans are their primary predator (often for the bushmeat trade), but Nile crocodiles, lions, and hyenas will take down individuals who stray from the troop or wander too close to the water.
The Egyptian god Babi was the deification of the Hamadras baboon, and was an aggressive, bloodthirsty, entrail-consuming god of the pre-dynastic Egyptian underworld. If your soul was deemed unjust on the scales of Anubis, you would be consumed by Babi, and not permitted into the afterlife. This role was played by Ammit (hippo-lion-crocodile) in some parts of Egypt, and Thoth (often portrayed as the ibis) was sometimes portrayed as the Hamadras baboon, too.
Because baboons were considered very virile, sexual creatures, Babi was usually portrayed with an erection, and was also prayed to in order to ward off impotence after death. His erection was said to be the mast of the boat that sailed the worthy souls to paradise in the afterlife.
Brehms Tierleben: Allgemeine Kunde des Tierreichs. Dr. Otto zur Strassen, 1912.
Bird Paintings of CG Finch-Davies. Claude Gibney Finch-Davies, 1920 (by the Transvaal Museum, 1984)
[Thoth as Baboon. 1400 BCE. British Museum, London.]