Carnivorous dinosaurs, such as relatives of Tyrannosaurus rex, were found in the same deposits as Sinosauropteryx. These included meat-loving species like Dilong and Yutyrannus, both of which were known to have excellent vision. It is therefore likely that Sinosauropteryx evolved its camouflage to escape predation by these larger dinosaurs.
Sinosauropteryx also had very long legs and the longest relative tail length of any known carnivorous dinosaur. Tails can help with balance and fast turns when running, so this dinosaur probably attempted to make hasty getaways when tyrannosaurs approached.
And camouflage can help the hunter as well as the hunted.
“We have direct evidence of predation by Sinosauropteryx, as one fossil has a complete lizard in its stomach representing its last meal — such a substantial one that it almost completely fills the abdominal cavity,” Smithwick said.
“The lizard has limb proportions suggesting it would have been a fast runner and was better suited to running in open areas. So this corresponds well to our results suggesting Sinosauropteryx was fast moving and lived in open areas,” he added.
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Taken together, the findings show how important feathers were to dinosaur survival. They not only helped dinosaurs to hide in their environments, but they also facilitated visual signaling among members of the same species, provided insulation, offered certain sensory capabilities in the way that whiskers do, and eventually enabled flight in birds.
Feathers, which in this case are in the fossil record, benefit today’s scientists, too. They can provide important clues about the lifestyle and habitat of long-extinct animals.
“We are hoping to push paleocolor forward to help address key questions about animal behavior and evolution in deep time,” Smithwick said. “We think that color patterns can tell us vast amounts about how extinct animals lived, and can give vital information that the bones alone would never tell us.”