Ten dinosaur myths you should unlearn before talking to four-year-olds
3: Big dinosaurs had butt brains
Some dinosaurs—such as the mighty sauropods and the armored Stegosaurus—had extra-large cavities in their hips. The wide spaces were associated with the neural canal, where the spinal cord passes, and so 19th century paleontologist Othniel Charles Marsh speculated that the space housed a “posterior braincase” that helped the dinosaurs coordinate their legs and tails.
But paleontologists now know that no dinosaur had a second brain. First, many different kinds of vertebrates have a slight expansion of the spinal cord in the vicinity of their limbs. This slight swelling of the nervous system helps regulate limb movement. But Stegosaurus and sauropods had even larger expansions that probably housed a strange feature called a glycogen body. This kind of tissue, seen in the hips of birds, might store energy-rich carbohydrates, although zoologists still aren’t entirely sure if this is the case. One thing is for sure, though—dinosaurs did not have brainy butts.