Attractive, Colorful Feathers Allowed Dinosaurs to Take Flight
Long before the ancient bird species Archaeopteryx first lifted off the ground, dinosaurs were donned in a colorful cloak of feathers - but why? The latest study shows that as the feathery display became more and more colorful over time, it in turn was more attractive to other members of the same species, bolstering communication, mating and breeding.
Recent research has shown that both birds and dinosaurs came from the same evolutionary tree, in which dinosaur arms eventually turned into bird wings with a fascinating disappearance and reappearance of bone in the wrist. Feathers, however, are a horse of a different color, and the new article "Beyond the Rainbow" in the journal Science attempts to explain why then-flightless dinosaurs developed them in the first place.
"Up until now, the evolution of feathers was mainly considered to be an adaptation related to flight or to warm-bloodedness, seasoned with a few speculations about display capabilities," the article's first author, Marie-Claire Koschowitz from the University of Bonn in Germany, said in a statement. "I was never really convinced by any of these theories. There has to be some particularly important feature attached to feathers that makes them so unique and caused them to spread so rapidly amongst the ancestors of the birds we know today."
The key is in the flamboyant colors of feathers. Dinosaurs could not only detect these colors by means of their red, green and blue color receptors - the same that humans have - but also via an additional receptor than humans lack, and crocodiles and birds possess, that probably let them see extremely short-wave and ultraviolet (UV) light as well.
This makes the world much more colorful for most animals than it is for human beings and other mammals. And previous research has shown that reptiles and birds, dinosaurs' closest living relatives, are influenced by color when it comes to communication and procreation.
So the boring brown, yellow, black and white tones of dinosaur hair, resembling mammal fur, eventually turned into the colorful plumage of large flat feathers.
Their broad surface area, created by interlocked strands of keratin, allows for the constant refraction of light, which in turn produces the vibrant blue, green, and metallic-like colors in the UV spectrum.
"This allowed dinosaurs to not only show off their colorful feathery attire," explained Dr. Martin Sander, who was involved in the study, "but to be warm-blooded animals at the same time - something mammals never managed."
Eventually, these large feathers would help biped dinosaurs take flight.