Today, the fayum of egypt is a desert. oligocene deposits have produced numerous fossil primates. the paleoenvironmental evidence suggests that during the oligocene the fayum was a:

Primate fossils found in Oligocene deposits suggests that the climate was wetter than it was today. Primates normally thrive in a tropical or subtropical environment. These environments support a diversity of flora that supports the diets of primates. They do not dwell in desert regions like the present environment of the Fayum Desert.  

It is used to during sexual reproduction between humans