If im correct, Reptiles are cold blooded so that means they need the sun.
Reptiles hate cold and they will freeze to death, so they will want to push all the blod away from their lungs!
another situation would be that if they are in danger or they want to hibernate (if they do that) they can just push blood out of their lungs with pressure.
If that helped please mark brainliest! <3
-procklown
