A sail-backed Dimetrodon from Earth's Permian period of time.

AGGRESSION • AMNIOTE • ANIMAL MOUTH • ANIMAL SCALE • ANIMAL TEETH • ANIMAL THEMES • ANIMAL • ANIMALS IN THE WILD • APEX PREDATOR • ARTFORM: SILHOUETTE • ARTWORK • BACKBONE • BACKLIT • BRIGHT • CARNIVORE • COLOR IMAGE • COLOUR IMAGE • CREATURE • DIGITALLY GENERATED IMAGE • DIMETRODON • DINOSAUR • DINOSAURS • EXISTENCE • EXTINCT • FIERCE • FULL LENGTH • FULL-LENGTH • GROWL • HISSING • HORIZON • HORIZONTAL • ILLUSTRATION • ILLUSTRATIONS • LARGE • LATERAL VIEW • MOUTH OPEN • NIGHT • NO PEOPLE • ONE ANIMAL • OPEN MOUTH • OPEN-MOUTHED • OUTDOOR • OUTDOORS • OUTSIDE • PALAEONTOLOGY • PALAEOZOOLOGY • PALEOBIOLOGY • PALEONTOLOGY • PALEOZOIC ERA • PALEOZOOLOGY • PAST • PELYCOSAUR • PERMIAN • PREDATOR • PREHISTORIC ERA • PRIMEVAL • PRIMITIVE • REPTIL • REPTILE • REPTILES • ROARING • SCIENCE • SIDE VIEW • SILHOUETTE • SILHOUETTES • SNARLING • SPECIES • SPHENACODONTIDAE • SPINE • STANDING • SUN • SUNSET • SYNAPSID • TOUGHNESS • VERTEBRA • VERTEBRATE • WILDLIFE • WITHOUT PEOPLE • ZOOLOGY