How the nose cooled dinosaur brains

Dinosaurs used their noses to not only breathe and smell but to cool their brains as well, said a study from Ohio University in the US.

"Dinosaurs were pretty 'nosy' animals. Figuring out what was going on in their complicated snouts is challenging because noses have so many different functions," said lead study author Jason Bourke.

To restore what time had stripped away, the team turned to the modern day relatives of dinosaurs - birds, crocodiles and lizards - to provide clues.

They took help from computational fluid dynamics, an approach commonly used in the aerospace industry and medicine, to model how air flowed through the noses of modern day dinosaur relatives such as ostriches and alligators.

The dinosaurs that fit the bill best were the pachycephalosaurs or "pachys", a group of plant-eating dinosaurs known for their several-inch-thick bone on top of their skulls.

It turns out that building all that extra skull bone resulted in ossifying soft tissues in other areas of the body such as the nose.

"When we cleaned up the fossil skull of Sphaerotholus, a 'pachy' from north Dakota, we did not expect to see these delicate scrolls of bone in the nasal region. We knew they must be nasal turbinates," noted co-author Emma Schachner from Louisiana State University.

Similar structures were found in a different 'pachy' species from Canada called Stegoceras.

Further analysis showed that the olfactory region of the brain was quite large which, along with the olfactory turbinates, suggested that Stegoceras had a good sense of smell.

"Stegoceras obviously had a pretty decent sense of smell but the odours were not reaching where they needed to go. We obviously were missing a piece of the puzzle," Bourke added.

When Bourke digitally inserted respiratory turbinates, the computer airflow simulations started to make more sense.

The findings suggested that turbinates also play another critical role - cooling the brain.

"Hot arterial blood from the body was cooled as it passed over the respiratory turbinates and then that cooled venous blood returned to the brain," concluded study co-author Ruger Porter, another Ohio University doctoral student.

The study appeared in the journal Anatomical Record.