The plated, spiked stegosaurs are perhaps the most perplexing paramours of all. Consider Kentrosaurus, a cousin of the more famous Stegosaurus. This armored dinosaur sported huge spikes on its lower back and hips that must have looked dangerous to males in the mood. I asked my paleontologist friend Heinrich Mallison of the Museum of Natural History in Berlin to evaluate the possibility that Kentrosaurus mated in the leg-over-back position using computer models he had previously developed to study how flexible the animal was. Mallison tested dinosaur sex positions in three dimensions and concluded that the traditional dinosaur sex position did not work for Kentrosaurus. If a male tried to throw his leg over the back of a crouching female, he would castrate himself on her sharp spikes. One hip spike in particular seemed to be placed to strike fear in the hearts of stegosaur suitors. These prickly dinosaurs must have had sex another way—maybe the female lay down on her side, and the male reared up to rest his torso over her hindquarters. Other dinosaur species no doubt assumed different positions, which future studies may reveal. By subjecting old bones to new technologies, scientists will start to understand how the dinosaurs proliferated over their astonishing reign.
This article was originally published with the title Love among the Dinosaurs.