Lizard 's size confirms elevated global temperature during the Cretaceous period . The cold - blooded animals relied on heat from their surroundings to cool their bodies . Man - made global warming in the 21st century pushing temperatures back up in that direction .
Lizard 's size confirms elevated global temperature during Paleocene greenhouse period . The cold-blooded animals depend on warmth from their surroundings to heat their bodies . Man-made global warming in the 21st century pushing temperatures back up in that direction .