The exceptional preservation of dinosaur feathers has allowed us to travel through time and to peer through the eyes of dinosaurs.
Recent research on dinosaur feather colors gave hints about sophisticated color vision in dinosaurs and contributed a convincing answer to one of the most hotly-debated questions in evolutionary biology: why did feathers evolve?
Some feathers are insulatory, keeping birds and dinos warm: these are the down feathers, with soft vanes and irregular shape (think: those feathers inside your pillow). These were likely the very first feathers, and probably evolved as a mechanism of thermoregulation. In fact, feathers allowed dinosaur body size to shrink much more quickly than in other lineages (because as you shrink, your surface-area to volume ratio decreases, and you lose heat more quickly).
But what about pennaceous feathers, or feathers with a rigid vane and defined shape? These are the feathers that are used in flight and communication, but for what purpose were they originally selected?
Researchers drew upon the following clues to form a hypothesis:
(i) pennaceous feather evolved independently in several maniraptoran dinosaurs, obviously not for flight
(ii) protofeathers (downy, less rigidly structured feathers) sacrifice color and structural signalling ability.
(iii) the demands of insulation were powerful in evolving dinosaur lineages, as body size shrank.
(iv) the sophisticated structure of pennaceous feathers has color signalling capacities -- both matte and iridescent-- far beyond that of fur, skin, or downy feathers.
Thus, it is likely that pennaceous feathers evolved to satisfy the parallel demands of signalling and insulation in early dino lineages.
This research is inherently interesting for its contribution to an ongoing debate, but it also has a bit of WOW! factor. Dinosaurs had splendidly colored feathers; they almost certainly had extraordinary vision as well. Indeed, the only remaining dinosaurs-- birds-- can see well into the ultraviolet and have 4 kinds of cones (color-receiving cells in the eye) compared to our paltry three. This adds an entire new dimension to their color perception- literally!
See the full article in Science here.
Dinosaurs may have seen the world in brilliant ultraviolet light and turquoises, along with the standard blues, greens and reds we can see. In a perspective in the Oct. 24 Science, researchers review recent findings about feathered dinosaurs and speculate on what the creatures could see and how their extraordinary vision may have been a main driver in the evolution of birds' flashy feather frocks. The team also proposes a detailed way to test the idea with fossil evidence of dinosaur feathers.