How Did Dinosaurs Have Sex?

Little is known about dinosaur mating, but recent research may provide a glimpse into how the prehistoric creatures had sex

silhouettes of two dinosaurs about to enjoy a romantic evening under the stars.
Two dinosaurs about to enjoy a romantic evening under the stars.
Stephen Leonardi

We may know a thing or two about Neanderthal sex, but there’s not much information available about the sex lives of Earth’s even earlier residents. Sure, you don’t have to be a paleontologist to know that dinosaurs must have had sex to reproduce. What may be less obviously apparent, however, is what exactly prehistoric coitus between these creatures would have actually entailed. Turns out, the experts aren’t sure either. There’s no fossilized evidence of dinosaurs getting it on, and according to CNN, it’s not even easy to identify whether dinosaurs are male or female based on fossilized bones. But while facts about dino sex are hard to come by, scientific advances in recent years have transformed our understanding of these species, even providing a glimpse into their sex lives.

For one thing, there’s evidence to suggest dinosaurs engaged in what one expert calls “prehistoric foreplay,” which involved male dinosaurs scratching the ground to show off their supreme nest-building prowess to potential mates. This is a mating behavior often observed today in birds, which are considered dinosaurs’ only living relatives, and fossilized “scrapes” left behind in 100-million-year-old rocks in the prehistoric Dakota Sandstone of western Colorado suggest dinosaurs engaged in the same pre-mating ritual.

“The scrape evidence has significant implications,” Martin Lockley, professor emeritus of geology at the University of Colorado Denver, said when the study was released in 2016. “This is physical evidence of prehistoric foreplay that is very similar to birds today. Modern birds using scrape ceremony courtship usually do so near their final nesting sites. So the fossil scrape evidence offers a tantalizing clue that dinosaurs in ‘heat’ may have gathered here millions of years ago to breed and then nest nearby.”

So what exactly followed a successful display of prehistoric foreplay? The logistics of dinosaur sex generally “defies the imagination,” as CNN puts it, but a recent discovery has provided a glimpse into what kind of genitalia dinosaurs may have been packing. Earlier this year, paleontologists at the University of Bristol and the University of Massachusetts Amherst announced they had discovered evidence of a dinosaur cloaca belonging to a Psittacosaurus. Many cloaca-having animals, including birds, mate by “cloacal kissing,” but Jakob Vinther, a paleontologist and senior lecturer at the University of Bristol’s School of Earth Sciences, believes that a male Psittacosaurus would have had a penis. “From what we can see, this cloaca would not have been suitable for cloacal kissing,” Vinther said. “It looks like it would have been penetrative sex.”

Still, the mechanics of prehistoric penetration remain largely unknown, so until science can tell us more about what it was like to do it dino style, we’ll have to rely on the admittedly limited powers of the human imagination for our dinosaur porn needs.

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