By all accounts they're hornier than we are. And that's saying something.
That's a survival strategy. Of all primates, humans and bonobo females do not exhibit any sign when they are fertile. All other primates do. Bonobo females have frequent sex with all the males in their troop and consequently the males have no idea who is the father of the children...consequently, they don't practice infanticide as do all other non-human primates.
BTW, human females are the only primates who give birth with the baby's head facing aft and often require assistance during birth. Other primate females can assist the birth of their own children...humans deliver 'backwards' because of the large head.