THE T-REX was a cool-headed killer thanks to an ‘air conditioner’ inside its head, according to new research.
The king of the dinosaurs had two huge holes in the roof of its skull – through which it could discharge heat.
Known as dorsotemporal fenestra, the stuctures housed blood vessels – not jaw powering muscles as first thought, it’s been claimed.
The groundbreaking discovery suggests T-Rex’s legendary bite force – said to be stronger than any animals that ever lived – will now have to be recalculated.
Lead author Professor Casey Holliday, an expert in anatomy, said: “It is really weird for a muscle to come up from the jaw, make a 90-degree turn, and go along the roof of the skull.
“Yet, we now have a lot of compelling evidence for blood vessels in this area, based on our work with alligators and other reptiles.”
The finding reported in The Anatomical Record overturns the previous theory that has stood for more than a century.
It is based on modern alligators that share a common ancestor with dinosaurs – and are related to T-Rex, the most fearsome predator that ever lived.
Large animals have to regulate their temperature to prevent being overwhelmed as the mercury rises.
The US team used thermal imaging devices that translate heat into visible light to examine alligators at a zoological farm in Florida.
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Prof Holliday, of the University of Missouri-Columbia, said: “It is really hard to get a picture of an alligator skull in the wild, because they are always off away from you and they are dangerous to approach.
“Being at the farm allowed us to get up and over fences and take images and video from the top down.”
The evidence offers a new theory and insight into the anatomy of T-Rex’s head, said the researchers.
Prof Holliday and colleagues compared the data with fossilised remains of dinosaurs and crocodiles, which also share the ancestor, to see how the skull holes changed over time.
Co author Larry Witmer, professor of anatomy at Ohio University, said: “We know that, similarly to the T-Rex, alligators have holes on the roof of their skulls, and they are filled with blood vessels.
“Yet, for over 100 years we have been putting muscles into a similar space with dinosaurs.
“By using some anatomy and physiology of current animals, we can show that we can overturn those early hypotheses about the anatomy of this part of the T-Rex’s skull.”
The beast would need to be able to shed large amounts of heat generated by its size, Prof Holliday said.
Having a built in ‘thermal window’ in its head would help.
The mechanism also changes our understanding of how some dinosaurs functioned in general.
The special sets of blood vessels in their skulls, located near where our temple is, could act as a way to regulate brain and body temperature.
Prof Holliday added: “Dinosaurs were likely more warm blooded than we used to think, more like birds than lizards.
“Being warmish blooded would let them not rely on environmental temperatures as much, like cold blooded lizards, but also control their own body temperature through internal means.”
