Scientists at Bristol University in England carried out the study, which showed that the fossil from the Eocene Epoch (33.9 to 56 million years ago) still contains remnants of melanin, a substance which dictates the colour of our skin.
The researchers, announcing their results on Monday, said that the shape of the melanin remnants in the bat's fossilized remains point to a clear answer – he was browny red – in other words very much like a modern bat.
At any rate, the team behind the discovery are delighted.
"This is a great leap forward in our understanding of how fossils are preserved,” said Dr. Jakob Vinther, who led the project, in a statement. "We now know how melanin is preserved and we have the methods to confidently detect it."
The team are also confident that the method they used to discover the ancient critter's skin colour can be applied to other fossils.
“We have now studied tissues from fish, frogs, and tadpoles, hair from mammals, feathers from birds, and ink from octopus and squids. They all preserve melanin, so it's safe to say that melanin is all over the place,” said Caitlin Colleary, a Masters student who worked on the project.
“Now we can confidently fill in some of the original colour patterns of these ancient animals.”