The fossil remains of an archaeopteryx were first discovered in 1861. It had feathers, so it was classified as a bird, the first bird, actually. But in the last 20 years, we've found an awful lot of dinosaurs of all kinds that had feathers, even dinos that weren't anywhere near related to each other. We know feathers help birds fly, but dinosaurs didn't fly (pterosaurs are not classified as dinosaurs) or so we thought. So why did dinosaurs develop feathers?
Dinosaur feathers came in all shapes and sizes, from tiny fuzz to plumes to brushy spikes. They also came in a range of colors. Some dinos had both scales and feathers, and a few were capable of flight. Yes, recent discoveries have found a couple of non-avian dinosaurs that could fly with their feathers. That sounds contradictory but "avian" in this case doesn't mean flight, it means the dinosaur line that evolved into birds. Each species had their own reasons for growing feathers, from warmth to camouflage to mating displays, or a combination of ways to use feathers. Read about some of these remarkable dinosaurs and what we've learned from them at Smithsonian.
(Image credit: Lucas-Attwell)