Optical Illusion Made Tiny Dinos Invisible

A recreation shows the dinosaur Psittacosaurus in a setting where it would be more visible to onlookers.

A small dinosaur used an optical illusion to become invisible in dense forests, helping to protect it from larger meat-eating dinos and other predators, a new study shows.

Well-preserved remains of the long-lost species, Psittacosaurus aka "Parrot Lizard," reveal that its body countershading created the camouflage. The findings are presented in the journal Current Biology.

Psittacosaurus fossil

"The fossil preserves clear countershading, which has been shown to function by counter-illuminating shadows on a body, thus making an animal appear optically flat to the eye of the beholder," co-author Jakob Vinther of the University of Bristol said in a press release.

Vinther's University of Bristol colleague, Innes Cuthill, added: "By reconstructing a life-size 3D model, we were able to not only see how the patterns of shading changed over the body, but also that it matched the sort of camouflage which would work best in a forested environment."

Humans and other animals to this day analyze patterns of shadow on an object to help identify what it is. We're usually unaware of this phenomenon. It just happens automatically as part of our visual processing.

The origins of the new study go back to Vinther's work as a Yale graduate student, when he first realized that structures previously thought to be artifacts or dead bacteria in fossilized feathers were actually melanosomes. These are small structures that carry melanin pigments found in the feathers and skin of many animals.

A Psittacosaurus specimen is so well preserved that it shows preserved melanin patterns, which can be seen with the naked eye. Figuring out the distribution of countershading proved to be tricky, though, as the extinct animal had been crushed flat and fossilized.

Read more at Discovery News