Are crocodiles warm-blooded or cold-blooded?

Both. When they bask in the sun, they absorb heat and their blood is warm. When the surrounding air temperature is cold, they cool down, and their blood is cool. Their body (and blood) temperature, is therefore variable. Unlike mammals or birds, they do not generate heat internally. So they have to bask in the sun to keep warm. That is why they get out of the water and lie down on the river banks. They will scamper back into the water when they sense danger or when they get too warm.