Humans do it. Our great ape cousins, the bonobos, do it. Now researchers have documented western gorillas mating face to face in the wild. This photograph, taken by a German research team in Nouabale-Ndoki National Park in the Republic of Congo, shows two western lowland gorillas embracing before engaging in what is politely called ventro-ventral copulation, as opposed to the front-to-back or dorso-ventral position favored by most primates. The female in the photograph, nicknamed "Leah," has a knack for being first: In 2005 the same researchers observed her using a stick to test the depth of a pool of water--the first known example of tool use by her kind. Before this photo, researchers had only seen western gorillas mating ventro-ventrally in captivity. Their population in the wild has declined by 60 percent in recent years owing to illegal hunting, habitat loss and disease, according to the Wildlife Conservation Society.