Happy Valentine's Day from the "Bleeding Heart" Baboons (aka Geladas)

Did you know that the nickname of the gelada is the "bleeding heart baboon?" Both males and females have an hourglass-shaped patch of skin on their chest that varies in color from dull pink to bright red. This chest patch is thought to be a sexually-selected signal, although we don't know its exact function. For females, changes in color may indicate changes in fertility associated with reproductive cycle. For males, the chest patch is hypothesized to be a "status" indicator. Dominant leader males have the brightest chests and subordinates have dull pink chests. Check out these photos and see for yourself:

Male (just after he became a dominant male)

 

Female (the swellings also indicate fertility).

 

Photographs by S. Liberman