Evidence of endothermy in Mesozoic dinosaurs involves the discovery of polar dinosaurs in Australia and Antarctica as properly as evaluation of blood-vessel structures inside fossil bones that are typical of endotherms. Evidence for real, vaned feathers related to the flight feathers of modern-day birds has been located only in the theropod subgroup Maniraptora, which involves oviraptorosaurs, troodontids, dromaeosaurids, and birds.