We know a great deal about non-avian dinosaurs from the bones and trace fossils they left behind. But those aren’t the only sources of information we have about the Mesozoic superstars. Paleontologists frequently turn to modern animals to better understand the anatomy and even the behavior of extinct dinosaurs. Unified through evolutionary theory, the traits of living animals can help us fill in the spaces between fossil bones.
Dinosaurs had muscles, stomachs, hearts, lungs, blood, and more. We know most of these things not because of direct evidence – preserved soft tissues are hard to come by in the fossil record – but because non-avian dinosaurs were vertebrates that shared a common ancestry with animals alive today. They had the same suite of soft tissue features present in frogs, lizards, birds, and mammals, including you, that are alive today. Really, most of the differences between these groups are the result of evolutionary tweaks to a body plan that has been conserved ever since four-legged fish started to clamber out onto the land around 375 million years ago.
And it’s because of these ancient, conserved traits that we can be sure dinosaurs had nerves. More than that, as paleontologist Mathew Wedel has argued, we can be certain that gigantic dinosaurs such as Barosaurus and Supersaurus had some of the longest nerves to have ever evolved, even though we’ve never found them preserved. In this short Dinologue video, I explain how we can be sure that sauropod dinosaurs had superlative nerves: