Rufous Dinosaur? Study Identifies Dino Feather Colors

Reconstruction of two Sinosauropteryx, sporting their orange and white striped tails. Original artwork © Chuang Zhao and Lida Xing.

Yes, Jurassic Park’s sequels crashed and burned like an asteroid. But you gotta admit—the dinosaurs seemed realistic, right? Maybe then…but after a paper appearing yesterday in Nature, any special effects team bent on a new dino flick should consider throwing some feathers in here and there—with particular attention to their color.

Using scanning electron microscopy, researchers  found pigment-bearing structures incased in the proto-feathers of non-avian dinosaur fossils. The structures, called melanosomes, also appear in early bird fossils and are identical to those found in living birds.

A zebra finch feather, showing two types of melanosomes: sausage-shaped eumelanosomes in the black parts of the feather, and spherical phaeomelanosomes in the orange part of the feather. Melanosomes are color-bearing organelles buried within the structure of feathers and hair in modern birds and mammals, giving black, grey, and rufous tones such as orange and brown. © University of Bristol.

Now, for the first time, researchers can begin reconstructing certain aspects of dino color. For example, the flesh-eating Sinosauropteryx probably had a tail sporting stripes alternating between white and chestnut or orange-brown; a crest along its back might have been rufous-hued as well.

The discovery helps quell a debate about whether or not dinosaurs’ pseudo plumes are true precursors to feathers. Some investigators have argued that they’re degraded collagen fibers. But the melanosomes described in the study are located inside the feather-like filaments, indicating that those filaments come from the epidermal layer, like modern feathers.

The fossil of a small flesh-eating Chinese theropod dinosaur Sinosauropteryx, a complete specimen in the Nanjing Institute. Short, bristle-like feathers run along the midline of the head, neck, and back, and all round the tail, forming irregular stripes. Samples were taken from a ‘dark’ stripe near the base of the tail (marked with arrow). Only phaeomelanosomes (a type of melanosome) were found in these feathers, indicating that the dark stripes were orange-brown in life. The pale stripes contain no melanosomes, so were probably white. © the Nanjing Institute.

The study also sheds light on the original function of plumes: Were they used for flight, insulation, or display? “We now know that feathers came before wings, so feathers did not originate as flight structures,” said Mike Benton, a paleontology professor at the University of Bristol who contributed to the findings, in a press release. And given the limited distribution of the simplest feathers in dinos such as Sinosauropteryx, they probably weren’t used at first for thermoregulation, either. So it seems that early feathers were intended for display all the way…which should make the box office happy.

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