How do you sex a fossil? | Elsa Panciroli

How can we tell if an extinct animal is male or female? And how did dinosaurs mate?

"It was a slit, like this," Vinther held his cupped hands side by side and opened and closed them, like a puppet's mouth. "That's it. That's what a dinosaur cloaca looked like."

For those who don't habituate the often explicit world of natural scientists, let me explain. A cloaca is the opening through which most vertebrate animals excrete their waste and have sex. It is an all-purpose exit and entry-point. Jakob Vinther from the University of Bristol, and his colleagues, are currently describing the only known dinosaur cloaca. It belongs to a spectacular Psittacosaurus specimen that preserves details of skin texture and even colouration. Their upcoming research will be the first ever scientific description of actual dino-privates.