It turns out dinosaurs weren’t cold-blooded killers after all, but nor were they warm. Researchers now believe that, extraordinarily, they could self-regulate their body temperatures.
By looking into dinosaur eggs found in Argentina and Mongolia, researchers from UCLA have established that temperature management may have separated dinosaurs from what we consider warm-blooded species (man, dog, bird etc) and cold-blooded species like crocodiles and lizards.
In a very simplified way of explaining it, warm-blooded endotherms don’t need the sun to heat themselves up, while cold-blooded ectotherms do.
Hotter than their surroundings
Long-necked titanosaur sauropods, closely related to the largest animals ever to walk the Earth, and small oviraptorids, closely related to the Tyrannosaurus rex, were found to have blood temperatures of 90oF and 100oF degrees respectively.
The researchers also looked into the environmental temperatures that these species lived in, finding that the smaller dinosaurs, in particular, were warmer than their surroundings.
Titanosaur sauropod eggs, pictured next to an excavation tool, via Gerald Grellet-Tinner
“The temperatures we measured suggest that at least some dinosaurs were not fully endotherms like modern birds,” UCLA’s Robert Eagle said.
“They may have been intermediate – somewhere between modern alligators and crocodiles and modern birds; certainly that’s the implication for the oviraptorid theropods.”
This would mean that, for a period of time, they could elevate their body temperatures, allowing them to move quicker, marking them out from modern crocodiles and alligators.
“If dinosaurs were at least endothermic to a degree, they had more capacity to run around searching for food than an alligator would,” added Eagle, whose paper appears in Nature Communications.
Of course Eagle and his colleagues are not the only researchers to look into this recently. Only last month Alaskan fossils revealed dinosaurs that frequented the tundra millions of years ago, again alluding to warmer blood.
A series of questions
Blood temperature is just one of the many key dinosaur bones of contention amongst scientists. Ah, lets call them fossils of contention.
Due to an understandable lack of knowledge in the area – we only know what has been discovered, and don’t know the extent of what is left to be found – plenty of supposition has gone into understanding the land before time, when dinosaurs ruled the Earth.
One of the many, obvious reasons as to why we know so little is because the animal kingdom survives by eating the animal kingdom. So even tiny, annoying “zombie worms” are out to spoil our knowledge.
We occasionally hear of new species to add to the many already known, like the “fluffy feathered poodle from hell” that was related to the Velociraptor, but there are still plenty more to find.
An Owen goal
Most modern thinking on the subject has evolved from the work of Richard Owen, a Victorian-era scientist who penned the ‘dinosaur’ name in the mid 1800s.
From fossil finds, early construction of what scientists thought they looked like resulted in cumbersome and, well, very fat visualisations.
Since then, things have evolved through to the creatures’ immense early-1990s popularity, with Jurassic Park signifying their ‘terrible lizard’ look, to today’s belief that they were, in fact, feathered specimens.
But that’s not to say they all looked the same, with some “chubby” lizard ancestors of dinosaurs recently discovered.
We’re always playing catch-up on a time that is getting further and further away from us, but Eagle’s discovery that some dinosaurs had “intermediary” levels of blood temperature could change our knowledge on the creatures yet again.
Main image via Shutterstock