This undated handout photo provided by the journal Science shows fossil body feathers of Inkayacu paracasensis, a nearly 5-foot-tall penguin that roamed what is now Peru 36 million years ago.
The fossilized feathers show that the flightless bird was a motley mix of reddish-brown and grey.
Penguins didn't always boast tuxedo-like black-and-white markings, according to a new study.
The discovery of the first ancient penguin fossil with evidence of feathers reveals the aquatic birds were once reddish-brown and gray.
The 36 million-year-old fossil represents one of the largest ancient penguins ever found.
The bird would have been 5 feet (1.5 meters) tall, and probably weighed twice as much as modern Emperor penguins, which average about 66 pounds (30 kilograms).
Its long, grooved beak suggests that, like modern penguins, it hunted by diving for fish.
Imprints of feathers in the rock around the bones could help researchers understand how modern penguin feathers evolved, said Julia Clarke, a paleontologist at The University of Texas at Austin and a co-author of the paper.
The fossil, a new species named Inkayacu paracasensis (or "Water King"), was discovered in the Reserva Nacional de Paracas, a desert preserve on the coast of Peru.
Researchers in the field noticed evidence of scaly skin on the fossil foot, prompting suspicion that more evidence of soft tissue might have been preserved.
When Clarke examined the specimen in the lab, those suspicions proved true."I turned over a flake of rock right near one of the wing elements, and right there was our first evidence of feathering," she told Live Science.
To find out what color those feathers might have been, the researchers examined the shape of the penguin's melanosomes.