One of the prehistoric animals looked at by the researchers were pterosaurs – flying reptiles which became extinct at the time of the dinosaurs.
The study suggests the relative size of the head crest compared to the body of the pterosaur was too large for it to have been dedicated to controlling the animal’s body temperature or its flight.
They also looked at mammal-like creatures called Eupelycosaurs, which lived before the time of the dinosaurs.
This group, which included the animals Dimetrodon and Edaphosaurus, carried large elaborate “sails” along their backs.
By using known relationships between body size and metabolic activity – the process behind heat generation – in living organisms, the scientists concluded that the features were “too exaggerated” to have played a role in the control of body temperature.