Researchers have made remarkable finds at sites such as Grand Staircase-Escalante, which the administration has shrunk
The paleontologist Rob Gay wasn’t expecting to find anything significant that day. He and a few of his students were scouting in the southeast Utah badlands in summer 2016 when they came across a hillside littered with hundreds of bones. Scattered haphazardly and protruding from the earth, they were the remains of of prehistoric reptiles that lived 220m years ago, at the same time as the earliest dinosaurs.
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.