Walking With Dinosaurs

Since the 1970’s, an ongoing debate concerning the blood of dinosaurs has engaged scientists and civilians alike. Although there is no direct evidence that indicates if dinosaurs were cold-blooded or warm-blooded, scientists do have some guesses.

Scientists have made two main arguments. Some believe that dinosaurs were cold-blooded creatures because of their relation to certain reptiles, like modern-day crocodiles. Crocodiles are cold-blooded, which means they cannot generate their own heat. Since these reptiles descended from dinosaurs, some scientists infer that dinosaurs, like crocodiles, were likely also cold-blooded.

In the 1970’s, however, a scientist named Bob Bakker tried to prove that not all dinosaurs were cold-blooded. Instead, Bakker thought dinosaurs could have been warm-blooded because they grew fast, moved swiftly, and represented a variety of carnivores and herbivores. Also, sauropods, the largest animals ever to live on Earth, showed no evidence that they needed insulation to conserve their body heat: this is a key point in Bakker's argument.

Today, scientists believe that dinosaurs were neither warm-blooded nor cold-blooded, but a mix of both. To distribute enough blood throughout their bodies, they would have needed active metabolisms like cold-blooded species but also four-chambered hearts to live like warm-blooded mammals.

We may never know for sure whether dinosaurs were warm-blooded or cold-blooded, but clearly some evidence exists to prove that this issue may not be so binary after all.

[Source: Walking With Dinosaurs]