Dinosaurs played a key role in humans’ evolution by paving the way for warm-blooded mammals, researchers believe.
Over millions of years the majestic beasts gradually shrank in size while adapting to have a higher metabolism.
This evolutionary process allowed dinosaurs to burn energy from food at a faster rate and regulate their own body temperature – leading the population to flourish.
Warm-blooded animals need a lot more energy than cold-blooded creatures such as reptiles and fish, which rely on environmental heat sources. However, they can live in a wider geographic range and have greater mobility and brain power.
Scientists have previously struggled to explain the origins of endothermy – the state of being warm-blooded – mainly due to the lack of fossil evidence.
However, researchers at the University of Chile say their latest findings shed light on how mammals became warm-blooded. They analysed how animals regulate their body heat, comparing this with different body sizes of theropods – a group of two-legged, three-toed dinosaurs from which all birds evolved.
Warm-blooded animals must balance how much heat their body makes – known as metabolic production – with how much is lost during physical activity or in cold weather. The new findings suggest metabolic rates rose steadily throughout most of the early to mid-Jurassic period, around 180million years ago.
They also indicate that a warm-blooded creature would need to shrink nine-fold to have the same energy needs as a cold-blooded creature of the same size.
For instance, a 43kg modern-day warm-blooded bird would have the same needs as its 370kg cold-blooded dinosaur ancestor, reports the journal Science Advances.
The study says the theropods population rose 30-fold as they profited from growing smaller as endothermy evolved.