Armor-Plated Dinosaurs Used Their Super-Long Nasal Passages to Keep Their Cool

Armor-plated dinosaurs probably had to deal with warm conditions. So how did these massive creatures keep their cool? Scientists have found that these dinosaurs had the capacity to modify the temperature of the air they breathed by using their long, winding nasal passages as heat transfer devices.

When animals, sweat, pant, move to the shade or submerge themselves in water, they're regulating their body temperatures. In fact, if they don't take these steps then they're liable to overheat. Yet armor-plated dinosaurs, called ankylosaurs, didn't possess all of these options to keep cool. That's why researchers decided to take a closer look at these creatures in order to see what methods they might have used to keep their cool.

In this case, the scientists used CT scans to document the anatomy of nasal passages in two different ankylosaur species. Then, the researchers modeled airflow through 3D reconstructions of these tubes. It turns out that the passageways would have given the inhaled air more time and more surface area to warm up to body temperature by drawing heat away from the nearby blood vessels. In other words, inhaled air cooled the dinosaurs' blood.

"There are two ways that animal noses transfer heat while breathing," said Jason Bourke, the lead researcher, in a news release. "One is to pack a bunch of conchae into the air field, like most mammals and birds do-it's spatially efficient. The other option is to do what lizards and crocodiles do and simply make the nasal airway much longer. Ankylosaurs took the second approach to the extreme."

It makes sense that the dinosaurs would possess such long nasal airways. After all, they were large animals, which meant that there was a lot more of them to cool down.

"Our team discovered these 'crazy-straw' airways several years ago, but only recently have we been able to scientifically test hypotheses on how they function," said Lawrence Witmer, one of the reserachers. "By simulating airflow through these noses, we found that these stretched airways were effective heat exchangers. They would have allowed these multi-ton beasts to keep their multi-ounce brains from overheating."