The flying bird dinosaur thing refers to a group of prehistoric reptiles that could fly called pterosaurs. Pterosaurs were not actually dinosaurs, but they lived alongside dinosaurs during the Mesozoic Era. They were the first vertebrates to evolve powered flight. Their wings were formed by membranes of skin that stretched from an elongated fourth finger to the body. Pterosaurs had hollow bones, large brains, good eyesight and other adaptations that enabled them to fly.
When did pterosaurs live?
Pterosaurs lived during most of the Mesozoic Era, also known as the Age of Reptiles or Age of Dinosaurs. This was a period spanning approximately 187 million years from about 252 to 66 million years ago. Pterosaurs first appeared in the late Triassic Period around 228 million years ago. They flourished throughout the Jurassic Period and until the end of the Cretaceous Period, when all pterosaur species went extinct along with the dinosaurs about 66 million years ago.
What did pterosaurs look like?
Pterosaurs came in a huge range of shapes and sizes, from small sparrow-sized forms to giant species with 10 meter (33 foot) wingspans. Their bodies were covered in hair-like pycnofibres. They had long tails, clawed feet and hands, and toothy jaws. The most distinctive feature of pterosaurs was the wing, composed of a membrane of skin called the patagium that connected the elongated fourth finger to the body. The first three fingers were small but had claws, and the pinky finger was greatly elongated to support the wing structure. The wings were powered by flight muscles attached to an enormous keeled breastbone.
How big were pterosaurs?
Pterosaurs showed a huge range of sizes. The smallest known pterosaur was Nemicolopterus, with a wingspan of just 25 cm (10 inches). Giant azhdarchid pterosaurs like Hatzegopteryx reached wingspans of over 10 meters (33 feet), comparable to that of a small airplane. The largest pterosaur species Quetzalcoatlus northropi had an estimated wingspan of 10.5 meters (34 feet) and weighed around 250 kg (550 pounds). The following table shows the wingspans of some typical pterosaur genera:
Pterosaur genus | Wingspan |
---|---|
Anurognathus | 0.5 m |
Pterodactylus | 1.5 m |
Pteranodon | 7 m |
Quetzalcoatlus | 10.5 m |
How did pterosaurs fly?
The wing structure of pterosaurs enabled them to fly in a number of ways. Smaller pterosaurs may have been capable of flapping flight. Larger pterosaurs like Pteranodon probably relied more on gliding and soaring flight, using air currents to stay aloft. The wing membranes connected to the hind legs, allowing greater control while airborne. Takeoff was assisted by quadrupedal launch – pushing off with all four limbs to generate momentum. Some pterosaurs may have been able to launch themselves into the air just using their powerful hind legs.
What did pterosaurs eat?
Pterosaurs occupied a variety of ecological niches, eating a range of different diets. Small pterosaurs ate mainly insects and other small invertebrates. Medium to large pterosaurs were carnivorous, feeding on fish, small vertebrates and even dinosaur eggs and hatchlings. Large toothless pteranodontids like Pteranodon probably scooped and filtered small sea creatures while flying over water. Later gigantic azhdarchids were terrestrial stalkers that ate anything from small dinosaurs to baby ungulates. There is also evidence that some early pterosaurs ate plants, seeds and fruit.
Did pterosaurs have feathers?
There is no evidence that pterosaurs had feathers. Instead their bodies were covered in a fur-like coating of filamentous pycnofibres, similar to mammal hair. Pycnofibres grew in various lengths and densities in different pterosaur species. They may have had various functions such as insulation, aerodynamics or display. Pterosaur pycnofibres were structurally different from both feathers and mammalian hair, indicating they evolved independently. Some scientists speculate pycnofibres share an evolutionary origin with dinosaur proto-feathers, but this has not been conclusively demonstrated.
Were pterosaurs closely related to dinosaurs?
Pterosaurs and dinosaurs shared a common ancestor and co-existed throughout the Mesozoic Era, but pterosaurs are not considered dinosaurs. Both are members of the archosaur group of reptiles. Dinosaurs belong to the sub-group Ornithodira, while pterosaurs are part of the distinct sub-group Pterosauromorpha. They independently evolved features associated with advanced archosaurs like erect limbs, five-fingered hands and relatively large brains. Pterosaurs are more closely related to crocodilians than they are to dinosaurs or birds. Birds are descended from a specific dinosaur lineage.
Did pterosaurs go extinct with the dinosaurs?
Yes, pterosaurs perished in the mass extinction event 66 million years ago that killed off all dinosaurs apart from birds. Their extinction is linked to the catastrophic meteorite impact and climate changes occurring at the end of the Cretaceous Period. No pterosaur fossils have been found in the Cenozoic Era following this extinction event. Competition with early birds may also have contributed to their decline. Birds evolved powered flight and occupied small aerial niches previously dominated by pterosaurs.
Could pterosaurs swim?
Most pterosaurs were not adapted for swimming and likely avoided water apart from skimming to feed. However, some more aquatic species may have been capable swimmers. Trackways show that pteranodontids and ctenochasmatoids occasionally landed on all fours on solid surfaces, indicating some ability to propel themselves on land using their hind limbs when needed. The wing membranes connected to the hind legs would have given them greater maneuverability in water, leading some researchers to speculate that later forms could take off from the surface after swimming.
Were there any herbivorous pterosaurs?
Most known pterosaur species were carnivorous, feeding on fish, insects and small vertebrates. However, some early groups appear to have been herbivores or omnivores. Fossilized pterosaur droppings (coprolites) containing seed husks indicate that the non-pterodactyloid species Anurognathus had a plant-heavy diet. Some other Triassic and Jurassic genera also show adaptations like multicusped teeth suited for processing plant material. Herbivorous pterosaur groups appear to have died out by the mid-Cretaceous as specialized fish-eating and terrestrial carnivore forms became dominant.
Could pterosaurs walk on two legs?
Tracks made by pterosaurs show they normally moved quadrupedally when on the ground. However, their hind limbs were capable of bearing weight and fully erect bipedal stances have been proposed for some species. Fossilized Azhdarchid footprints have been found indicating an upright two-legged walking gait, leading researchers to speculate they spent more time terrestrially stalking prey than other types. Skeletal analyses also suggest some later pterosaurs had hip and leg proportions suited for regular bipedal locomotion. Though quadrupedal, pterosaurs appear to have been more maneuverable on land than traditionally depicted.
Did pterosaurs migrate long distances?
Some pterosaur species appear to have migrated seasonally like modern birds, while others were more sedentary. Pteranodontids like Pteranodon sternbergi were likely migratory, traveling long distances between inland nesting sites and coastal feeding grounds. Giant azhdarchids were also capable of flying thousands of kilometers between continents, indicating some migratory behavior. However, contemporaneous genera like Anurognathus seem to have been year-round residents in stable upland habitats. Migratory tendencies likely depended on size, flight ability and habitat preferences of different pterosaur groups.
Conclusion
Pterosaurs were an extremely successful group of flying reptiles that thrived for over 150 million years alongside dinosaurs, adapting to fill a huge variety of aerial niches. They were the first vertebrates to evolve true powered flight. Their unique wing structure enabled them to occupy roles ranging from small insectivores to giant terrestrial predators. Pterosaurs were diverse and widespread but went extinct along with non-avian dinosaurs 66 million years ago, likely due to catastrophic climate changes and ecological competition with early birds.