Bringing Sexy Back: Leah and Partner. Photo:Thomas Breuer - WCS/MPI-EVA.

Scientists from the Wildlife Conservation Society and the Max Planck Institute for Evolutionary Anthropology were minding their own business recently while studying western lowland gorillas in Nouabalé-Ndoki National Park in the Republic of Congo when they saw what no one has ever recorded: Leah and her sweetheart trying to make baby gorillas through face-to-face copulation. Curiously, Leah was also the first wild gorilla to be observed using tools, scientists reported in 2005. (She used a stick to determine the depth of a pool of water before wading into it.) A true pioneer, indeed.

Face-to-face (or, technically, ventro-ventral) copulation is extremely rare in the animal kingdom. Before lowland gorillas joined the club, only people and bonobos (a chimp cousin known for really, really enjoying recreational sex) had been known to look at their partner while mating. From time to time, a scientist in the field reported seeing mountain gorillas mate face-to-face, but the sightings were like those of Bigfoot: no photo, no count. Captive western gorillas have also been known to mate face-to-face, but scientists always wondered if that was an artifact of living in a zoo, not natural.

Thomas Breuer of the Max Planck says, “we can’t say how common this manner of mating is, but it has never been observed with western gorillas in the forest. It is fascinating to see similarities between gorilla and human sexual behavior.” Let that serve as inspiration for the 14th.