Most snakes reproduce sexually. A male and a female mate — the male inserts one of his two penises (called hemipenes) into the female's cloaca (an orifice for waste and reproduction), using ...

David Attenborough tells the story of the animal that once bewildered scientists: the chameleon. Watch the full documentary David Attenborough's Natural Curiosities on BBC Select. Jeffrey Sherman ...

Since the field’s beginning in the 1800s, researchers have spent two centuries studying and documenting the remarkable diversity of snake and lizard penises, actually called “hemipenes” (singular: ...