if dinosaurs were reptiles and cold blooded, what would cause the evolutionary step to become warm blooded and birds as it’s said that birds are the closest living relatives of dinosaurs.

Question

if dinosaurs were reptiles and cold blooded, what would cause the evolutionary step to become warm blooded and birds as it’s said that birds are the closest living relatives of dinosaurs.

In: Biology

Answer 1

In addition to what’s been said, you may have noticed that only birds and mammals among extant animals have fibrous insulation. This only makes sense: if you’re warm blooded you need insulation, whereas if you’re not, you want to be able to expose your body to the sun to warm it up.

Feathers that were not aerodynamic evolved among dinosaurs before flight. In fact, most or maybe all therapods had something akin to feathers at some point in their lives, and seems likely that its primary purpose was insulation.

Larger dinosaurs, it should be added, were basically beyond needing to worry about it one way or the other. Once you reach a certain size, you are basically warm blooded by default because your mass is so much more than your surface area.