The Dinosaurs' Crest. What Was It Good For?

Researchers debated for decades about the function of the duck-billed dinosaur's massive but hollow crest. One popular idea, at least among scientists, has now been put to rest - the crest had nothing to do with the sense of smell.

The technical name of the duck-billed dinosaurs is lambeaosaurus. They were one of the largest herbivorous dinosaurs that lived 85 million to 65 million years ago and their most recognizable feature is their crest.

The fact that the crests were hollow generated all sorts of far-fetched theories, e.g. some speculated they were brain coolers. One of the most popular theories said that that crests increased the dinosaur's sense of smell. For example DinoDictionary.com writes: "Resembling Corythosaurus, Lambeosaurus' nostrils extended up from the snout and through its hollow crest."

However, David Evans, a PhD student in zoology at the University of Toronto, has now been able to use a reconstructed brain cavity to rule out this theory. The reconstruction of the dinosaurs' brain cavity using well-preserved fragments of fossilized bone allowed him to create a model of lambeosaurs' brain. The brain is approximately the size of a human fist.

"From the brain case, there's no indication that the nerves curled upwards into the crest, as we would expect if the crest was used for the sense of smell," Evans says. "It appears that the brain changed very little from their non-crested dinosaur ancestors, and that the primary region of the sense of smell was located right in front of the eyes - and coincidentally, that's where it is in birds, crocodiles, mammals and basically all four-legged animals."

The findings add weight to other two currently popular theories: that the crests were used to create resonant sounds to attract mates or warn of predators, or that they were used for visual display and had a function of attracting mates, similar to crests of some birds.