The swollen red bottom of a female baboon has long been thought to be an irresistible come-hither signal for males. … The female baboon’s famously red bottomis a sign of sexual readiness; when female baboons ovulate, their butts swell, making it clear to available males that they are fertile.

Why are baboon buttocks blue?

A baboon’s butt tissue is arranged somewhat like the illustration above so that blue photons are reflected and all of the other photons (like the red ones) are absorbed. Only the blue light makes it out and gets into our eyes. This is why we see we see blue monkey butts!

Why are male baboons bottoms red?

The swollen red bottom of a female baboon has long been thought to be an irresistible come-hither signal for males. … In fact, a male baboon’s (Papio cynocephalus) motivation to mate with a female is based more on the length of time since her last pregnancy than on the size of her derriere, scientists have found.