These frogs put the “group” in “group sex”—and that helps them thrive.
Of all vertebrates, gray foam-nest tree frogs exhibit the most extreme form of simultaneous polyandry, or a female mating with multiple males, says behavioral ecologist Phillip Byrne of the University of Wollongong in Australia.
After a heavy rain swells pools in the African landscape, male frogs gather in poolside vegetation and call for mates, while females in the pools absorb water through their skin. When she’s hydrated enough, a female heads for an overhanging branch. En route she is amplexed—gripped in a sexual embrace—by a male.