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It’s been described as the most impressively preserved dinosaur fossil ever found – and now it’s beginning to reveal its secrets. Surprisingly, despite its large size and heavily armoured body, Borealopelta markmitchelli apparently had predators – judging by the fact that it evolved camouflage.

The astonishing 110-million-year-old specimen of B. markmitchelli was discovered in 2011 in an oil sand mine near Fort McMurray in Alberta, Canada. The fossil is one of the few dinosaurs preserved in 3D; it has a complete head, neck and right forelimb, and a partial torso and left forelimb.

“Normally when we find a dinosaur we find bits and pieces of skeletons, and occasionally soft issue,” says at the Royal Tyrrell Museum of Palaeontology in Drumheller, Canada. “In this case we have all the skin preserved in the front half of body – so it actually looks like it looked back in the Cretaceous.”

B. markmitchelli, which Brown estimates weighed 1300 kilograms and was 5.5 metres long, belongs to a group of dinosaurs called ankylosaurids that all had body armour. But Brown’s team thinks this particular ankylosaurid also had a form of camouflage called counter-shading, which suggests it had to hide from predators despite its impressive size.

Giant predators

One of the simplest and most common forms of camouflage, counter-shading means an animal is darker on top and lighter underneath to conceal its shadow from sharp-eyed predators – think of a deer. When sunlight hits the body from above, an animal’s back is well lit and its belly in shade, so this opposite colour pattern makes the animal harder to see.

Examining geochemical markers in the ancient skin that indicate different pigments, Brown’s team determined the dinosaur’s reddish-black skin hue was most pronounced on top and disappeared on its underbelly.

Many animals use camouflage to conceal themselves from predators. However, Brown points out that the largest herbivores living today, like rhinos and elephants, don’t exhibit counter-shading. The biggest animal today that has camouflage markings is the giraffe. The only other dinosaur .

Brown thinks this may be in part because today’s predators are more smell-oriented than the carnivores of yesteryear – and also because predatory dinosaurs could grow so large. He and his team say B. markmitchelli may have experienced high predation pressure from beasts like Acrocanthosaurus – a Tyrannosaurus rex-like dinosaur roughly 11.5 metres in length with a short sail along its back.

at the University of Toronto, Canada – who also works at the Royal Tyrrell Museum but wasn’t involved in the new analysis – says the camouflage claim may need to be examined more thoroughly. She says that melanosomes – pigment cells in skin – are difficult to distinguish from bacteria, which can have a similar size, shape and chemical signature. “It doesn’t necessarily mean they’re wrong in their reconstruction,” she says. “But it’s tricky to be really confident, even on something as beautifully preserved as this particular specimen.”

Read more: Masters of disguise