(CNN) -- Penguins didn't always come in black and white, paleontologists said Thursday, citing the discovery of a 36-million-year-old fossil of a bird that, in its day, waddled nearly 5 feet tall.
A specimen found in Peru showed that at least some of the giant penguin's feathers were reddish brown and gray, said a University of Texas at Austin paleontologist who was the lead author of a paper appearing in Thursday's online edition of the journal Science.
The new species, "Inkayacu paracasensis," or "Water King," was bigger than the Emperor penguin, the largest living penguin now.
"Before this fossil, we had no evidence about the feathers, colors and flipper shapes of ancient penguins. We had questions and this was our first chance to start answering them," paleontologist Julia Clarke said in a statement.
The color pattern of living penguins is a more recent innovation, said scientists. The fossil shows the flipper and feather shapes that evolved early to make them such powerful swimmers. The fossil also has preserved evidence of scales and feathers.
Bird feathers get some of their colors from the size, shape and arrangement of nanoscale structures called melanosomes, the report said. Modern penguins and the fossil differed in the formation of melanosomes.
Inkayacu paracasensis was discovered in 2007 by Peruvian student Ali Altamirano in Paracas National Reserve, researchers said.
The National Geographic Society, which along with the National Science Foundation, provided funding for the research, said it's not exactly clear why modern penguins come in black and white.
Perhaps it was a response to the rise of new penguin predators, such as seals, said Clarke, according to National Geographic.
In a phenomenon called countershading, modern penguins' white bellies camouflage the birds against the sky, at least from the vantage point of a swimming predator looking up. To a predator looking down, a penguin's black back vaguely matches the dark depths below.