Prehistoric Predators: The Biggest Carnivores of the Prehistoric World

Prehistoric Predators: The Biggest Carnivores of the Prehistoric World — page 7
A lone Dimetrodon is silhouetted against the morning sky Paleontologists used to think that the protomammal turned its big sail toward the sun to help it warm up each morning But newer evidence suggests that those long spines and the skin between them evolved as a display structure Such a big flashy ornament would have helped these predators figure out who was who as they walked across the Permian landscape and Dimetrodon may have even used the sails as biological billboards to show off during the mating season