Nevertheless, he says, the researchers' conclusion that plant-eating dinos were at an early disadvantage because they were particularly energy hungry depends on the assumption that they were warm-blooded whereas other reptiles were cold-blooded, "a pervasive idea that has not been entirely established".
Reptilia (Reptiles) - cold-blooded, egg-laying, with scales or scutes and (usually) three-chambered hearts.
Reptiles are cold-blooded, meaning they don't have body heat.
Reptiles are "cold blooded", i.e., they rely on the heat from external sources (a condition called ectothermic) such as the sun to maintain their body temperature, which fluctuates greatly according to the ambient temperature (a condition called poikilothermy).
When he went to bed, the rat came with him, and if he woke in the dark of the night — and he did, twice, three times — he felt its presence beside him, its spirit, its heart, its heat, and it was no reptile, no cold thankless thing with a flicking tongue and two dead eyes, but a creature radiant with life.
Many studies have hinted that dinosaurs had an active lifestyle, a sign of warm blood, but their bones tell a different story: They often contain tree-ring-like features, called lines of arrested growth (LAGs), which have been linked to lengthy episodes of slow metabolism in a variety of modern-day reptiles and other cold-blooded creatures.
Crocodilians are also think tanks, and will engage in sophisticated behavior that leaves most reptiles in the cold.
"They are cold-blooded reptiles," he told Mack.
Cold-blooded reptiles they may be, but they are also ardent and single-minded.
Most people are aware that land turtles are cold-blooded reptiles that live long lives, are inclined to hibernate, and move through the world at a slow pace.
The original movie, adapted by Michael Crichton from his best-selling book, shattered public perceptions by portraying dinosaurs as fast-moving, warm-blooded, birdlike creatures, not sluggish cold-blooded reptiles.
