For millions of years, their amazing flying skills have made them rulers of the sky – but in their quest for biology-inspired flight technologies, pterosaurs and other petrified aerial acrobats have been largely overlooked. Scientists say this should change now. In the publication, they show the potential of modern palaeontology as a source of inspiration for the development of new aviation technologies.
Bionics is a technical term: for a long time, researchers and developers have been inspired by models from nature to meet various technical challenges. Because biological concepts are highly optimized as they are partly based on millions of years of evolution. Particularly in aviation, attention was paid to nature acrobats – birds, bats and insects. To this day, they provide an important impetus for the concept of designing airplanes and drones. But looking into the past of ‘animal aviation’ is unusual in bionics, researchers led by Liz Martin-Silverstone of the University of Bristol said.
Paleontology as a source of inspiration for technology?
They explain that one reason is that paleontological information has traditionally seemed rather imprecise as it was often based on the study of fragmentary fossils. Martin-Silverstone and her colleagues have now questioned the extent to which it really is. They assessed research on pterosaurs and other fossil flight specialists. She focused on the question of whether the potential of biology-inspired flight technology was emerging.
According to the researchers, there are several pterosaur fossils that provide extremely detailed insight into the anatomy of their wings and thus their flight abilities. What is particularly interesting about these animals is that their concepts have been successful for a very long time and have made amazing achievements possible: their numerous representatives have flown in the sky for about 160 million years – much longer than the birds before. They also created the largest and heaviest creatures that ever took to the air: with a wingspan of more than ten meters, these giants once rose above the horizon. Pterosaurs did not become extinct because they were “obsolete models”: an asteroid impact some 65 million years ago pushed them violently off the evolutionary scene along with the dinosaurs.
Some fossils are worth a look
From a bionics point of view, the main question is how these large animals floated in the air and how their volatile membranes were able to withstand the aerodynamic loads. Because these are aspects that are still technically challenging. “There are two or three pterosaur fossils that have been preserved in absolutely amazing detail that show different layers in the wing membranes and can therefore give us a glimpse into their fine structure,” reports Martin-Silverstone. Some of the fossils are also so well preserved that you can see the connections between the membranes and the body, the researchers say. “Even if the shape of a wing is not clearly visible, knowing the anchorage of the membrane, you can model the effectiveness of different wing shapes and determine which ones work best in the wild,” says Martin-Silverstone.
There also seems to be evidence that pterosaurs used technically interesting starting methods. A jump launch that allows some birds or bats to take to the air in one fell swoop has proven difficult so far. As the size increases, this also becomes problematic for the birds. However, a species of pterosaur that weighs more than 200 kilograms has apparently developed alternative methods of catapulting into the air. According to a hypothesis by co-author Mike Habib of the Los Angeles County Museum of Natural History, it was possible to allow for special muscle adaptations as well as elbow and wrist features to allow the animals to take off without much run. “Closer exploration of these options can help solve technical problems, for example in the design of some drones,” says Martin-Silverstone.
Ancient concepts with potential
Pterosaurs can also provide insight into how flight instability in the air can be prevented, the researchers report. Because, unlike some engineering concepts that become unstable in high winds, it seems pterosaurs have evolved strategies to stop the flapping of wide wings. “To date, there is still room for improvement in the development of flight suits with membranes that are able to withstand pressure in flight. If we understand how the pterosaur wing membrane was constructed, we might be able to design better solutions, ”says Martin-Silverstone. As she and her colleagues report, some fossils certainly have the potential to do so.
In addition to pterosaurs, scientists are also looking at representatives of winged dinosaurs. Consequently, some created concepts that also produced technically interesting aerodynamic effects. An example is the so-called Microraptor. It had feathered wings and legs and probably flew with some sort of biplane strategy. Another small dinosaur, in turn, linked the feathers to a bat-like membrane, which apparently also gave it special abilities. “If we only look for inspiration in modern animals, we may ignore many options that might be technically useful,” said Martin-Silverstone.
Therefore, she and her colleagues want to use their publication to encourage scientists to work more closely together: “We want developers to turn to palaeontologists if they are looking for solutions to flight problems, because there may be an extinct creature that can serve as a model,” concludes Martin-Silverstone .
Source: Cell Press, Specialist article: Trends in Ecology & Evolution, doi: 10.1016 / j.tree.2020.03.005