Bonobo apes, sometimes referred to as the "make love not war" ape, are known for their high octane sex lives. Similar to humans (with whom they share 98% of their DNA) and different from other primates, "hooking up" is more than procreation; the species uses sex to show affection, relieve stress, thwart conflict, and simply for fun. Researchers have now observed that bonobo females also have sex for bragging rights.

Like a bunch of boys in a high school locker room, bonobo females broadcast their conquests to enhance their social status. When love locked with a high-ranking male, saucy lady apes shout out characteristic "copulation calls" so others will know exactly who is zooming whom. A new study reveals that females also cry out when having sex with other gals-but only alpha females. "These females are climbing social ladders," Zanna Clay, a postdoctoral researcher at Emory University who worked on the study, explained to LiveScience.

Eminent anthropologist Frans de Waal has dubbed bonbos "pan-sexual." They will fool around in basically any combination. They are also the only non-human species observed to tongue kiss, copulate face to face, and practice oral sex. "By engaging in these social-sexual interactions, they are showing off their social abilities," says Clay. In layperson's terms, that's sleeping one's way to the top.