One of the frustrating things about studying long-extinct animals is how thoughtless they were. Dinosaurs — already factually* proven to be the coolest creatures to ever exist — were terribly bad at leaving us good examples of their soft tissues to study. Instead of lining up in neat orderly rows under ideal conditions for long-term fossilization, they just died everywhere. This has made it vastly more difficult to study them appropriately. In most cases, fossilization only preserves bone, though faint markings, scratches, or preserved ‘shadows’ sometimes still show where soft tissue existed.
Because we can’t examine soft tissue directly, paleontologists have to study them indirectly, by examining the bone structures that were preserved for millions of years and comparing them with creatures that still exist today. By tracing the evolutionary lineage of still-extant creatures backwards in time to when it converges with now-extinct creatures, scientists can observe how these features evolved and intuit some aspects of how older structures might have functioned.
Researchers examining the skull of Tyrannosaurus Rex have published a paper arguing that these creatures effectively had air conditioners built into their skulls. Maintaining appropriate body temperature can be a challenge in large animals, and many creatures have adapted various strategies for solving the problem. Elephants have large ears to radiate heat from blood vessels and can flap their ears to create cooling air currents. Some large animals spend a great deal of time in or near water to keep their own body temperatures regulated. Some are active mostly at night when temperatures are lower.
Tyrannosaurs, on the other hand, had holes in their skulls. These holes, known as dorsotemporal fenestrae, have long been thought to function as massive anchors for the creature’s huge jaw muscles. These muscles were thought to entirely fill the cavity when the creatures were alive. According to new research published in The Anatomical Record, however, muscles weren’t the only thing tyrannosaurids packed into the space. These fenestrae may have served a dual function by providing important cooling capability as well. They write: