We don't know exactly what dinosaurs looked like, but feathers discovered in 80-million-year-old amber provide new clues.
Paleontologists made this discovery of feather specimens near Grassy Lake in southwestern Alberta, Canada, and described the results in the journal Science.
Researchers don't know which feathers were actually from birds that flew and which might have been from theropod dinosaurs, but the filament structures resembles those seen in other non-avian fossils.
There appear to be two types in the sample: those resembling the feathers of modern birds, and "protofeathers," which are similar to the hair-like structures found in a halo around dinosaur specimens from China in early early Cretaceous rock. Those simpler feathers in the amber, which differ from what modern birds have, may have come from small, meat-eating dinosaurs.
"Short of finding a dinosaur trapped in the amber itself, it’s the best we can do," said Ryan McKellar, a paleontology graduate student of the University of Alberta and lead author of the study.
Although the feather fragments themselves are tiny - ranging from only 2 to 8 millimeters in length - they are preserved in 3D in extraordinary detail, scientists say.
Even some of the pigment remains, so we know what color feathers may have covered these prehistoric creatures. The dinosaur-looking ones display a pale to dark brown color, while the bird-like feathers have a wide range of appearances: There are white downy feathers, as well as flattened, veined feathers of black, brown, and lots of shades in between.
The dinosaur-looking feathers resemble mammal hair-fur and would be useful for things like insulation, and perhaps camouflage and display. The bird-like feathers are even more specifically formed: Some fragments have structural adaptations for flight, and others show characteristics of being able to pick up water, so they could carry water back to their nests or dive better.
How do feather fragments get so well preserved?
About 80 million years ago, these feathers likely blew into some tree resin and, over time, it hardened into an intermediate stage called copal, which then turned to amber. The resin hardens as its volatile component dissipates, and what's left behind is similar to plastic in structure.
The amber used in jewelry today is usually about 17 million to 40 million years old; more than 65 million years old is too brittle for decorative purposes, meaning there probably aren't dinosaur feathers in your mother's amber necklace.
But insects do often get trapped in amber; in fact, McKellar and colleagues found a feather fragment trapped in a spider web in one of the pieces of amber. That's right: There were spiders making spider webs 80 million years ago.
"This is sort of the first large survey we’ve had from a single amber deposit," he said.