US scientists set to reveal the true colour of dinosaurs

A new technique that identifies the hue of ancient birds may help a Yale team with bigger beasts

It is a question that has baffled the greatest scientific minds – and those of the average seven-year-old: what colour were dinosaurs?

Now a dramatic breakthrough in fossil examination has sparked a race to discover an answer that may satisfy the scientific community as well as anxious crayon-wielders. A research team at Yale University believes it has established a technique that can identify the colour of fossilised feathers and fur. Preliminary results suggest that the true colours of dinosaurs may soon be revealed.

A team headed by Professor Derek Briggs, director of Yale's Peabody Museum of Natural History, discovered that tiny fossilised structures previously believed to be the remains of bacteria were in fact carbon deposits called melanosomes, which indicate the colour pattern of modern birds' feathers.

Initially the scientists could identify only black or white bands but further developments now mean they can see the structure, which they know is responsible for iridescence or colour sheen. The colour of the feathers is identifiable from the shape of the structure.

"This is, to our knowledge, the first evidence of preservation of a colour-producing nanostructure in a fossil feather and confirms the potential for determining colour differences in ancient birds and other dinosaurs," the research paper, published this week in the journa Biology Letters, said.

After examining fossilised feathers from Messel in Germany, Professor Briggs and his team say the creature that sported the feather was black with a "strongly lustrous iridescent blue, green or coppery sheen", similar to the modern swift.

"The structures are such that we can be very confident that these feathers were iridescent," Professor Briggs said. "We don't know which bird the feather was from as they have been separated from the skeleton. In the future this won't happen if we think there is interesting feather data. There are feathered dinosaurs, mostly found in China, from the Jurassic and Cretaceous period. It would be astounding to find the colour of these feathers and this is very exciting."

He added that although only dark blue and reddy browns can be identified at the moment, analysing the same deposits in modern birds and butterflies should open the way to identifying yellows, blues and oranges.

Dinosaurs, which date back at least 65 million years, have fascinated the world since their enormous bones were first identified in the 19th century. While great strides have been made in understanding their behaviour, knowing their colour would open the door to information previously thought impossible to gain. Modern animals have evolved colour on their fur or feathers for important survival reasons, such as camouflage and mating, for example.

"Feathers are important for camouflage and sexual display," Professor Briggs said. "So we can learn a lot about behaviour. There's also a possibility that fur colour could be identified, so we may be able to work out the colour of extinct mammals. Now that the technique is known the race is on."