This results in a net rise in core temperature. Seebacher and colleagues show that large crocodiles get round this by regulating their temperature behaviourally. That is, they go in and out of the sun at various times of day, a pattern changing with the seasons, to keep their core temperatures stable. If dinosaurs were 'cold blooded', like crocodiles, they would have had to have done the same thing. Indeed, large dinosaurs living in the tropics might have had to have been completely nocturnal in the summer months.
Conventional wisdom holds that the metabolism of reptiles gets slower with increasing size.
The new results show that this is true only up to a point. In reptiles more massive than about 50 kilograms, metabolism actually increases with mass. This would have allowed large dinosaurs to be much more physically active than one would have predicted, given a steady core temperature independent of mass. This result will be of interest to palaeontologists speculating on the physiology of dinosaurs, and whether or not they were 'warm-blooded', like birds and mammals. Warm-blooded animals have physiologies that keep the body at an even temperature, despite external conditions.