Not too surprising forest based dinosaurs turned out to be good at camouflage. That it is similar to marine adaptations and well understood is welcome. It will never be controversial.
It is also a reminder that all creatures uses camouflage to some degree, but specifically for the environment they are meant to prosper in. It also serves to limit where they might be found.
Thus so many creatures actually evade counting with great ease that most of our statistics need to be really thought through. When there is ample prey species, one needs to remember that their predators are hiding from you even ten feet away. Which makes predator counts rather challenging.
Recall our conjecture that the cougar and the Sasquatch share similar ranges and the same key game in the form of the deer. Thus right away i have likely doubled the available predation of the deer..
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Dinosaur Camouflage Revealed In Living Color
Do you see what I see? This model of a Psittacosaurus of the early Cretaceous might stand out to human eyes, but its coloration was likely an effective defense against predators. Credit: Jakob Vinther, University of Bristol and Bob Nicholls (Paleocreations.com)
What do dinosaurs have in common with great white sharks? Other than being awesome? Countershading, that’s what.
Researchers were able to reconstruct the color patterns on one
plant-eating dinosaur from China and discovered it was rocking a look
similar to the apex predator of Jaws, but for very different reasons.
Countershading — areas exposed to the most light are dark, while
those most likely to be in shadow are light — is a common camouflage
pattern in many of today’s animals, especially among fish and marine
mammals.
It’s called countershading because it seems to run counter to what
would be a smart strategy. You might think the lightest parts of an
animal would be the areas that get the most light. Nope.
Take the great white shark for example: When viewed from below, its
pale belly blends in with lighter water nearer to the surface, and when
viewed from above, its dark back disappears against the shadowy depths.
I say “blends in” and “disappears” with poetic license, because what
really happens is that the contrasts of the animal and its shadow are
reduced, flattening its three-dimensional shape against its background
and making it harder for predator or prey to see it.
Enter Psittacosaurus (which I always think of as the Tacosaurus because it’s pronounced with the stress on the “taco.” Mmm. Tacos).
Researchers took a close look at one speciman of the ornithischian dinosaur…actually, they took a close and very fancy look, using crossed polarized light photography and laser-stimulated fluorescence imaging.
It’s less important to know how exactly these technologies work and
much more important to tell you what the researchers found: different
patterns of pigmentation emerged thanks to their detection of preserved
melanosomes, cellular structures responsible for making and storing
melanin.
Artist rendering of countershady character Psittacosaurus. Credit: Bob Nicholls.
Two-Tone Tacosaurus
According to the study, published today in Current Biology,
areas of higher and lower melanosome concentration clearly showed the
animal had a darker top and lighter underside, with the palest area
being the lower abdomen.
Okay, so what is a very much land-based herbivore doing with the same
camo strategy as a marine apex predator? To find out, the researchers
built two life-size models, painting one gray and the other with an
approximation of the animal’s actual appearance (while the researchers
can’t say for certain the dinosaur’s actual colors, they based the
pattern on the preserved clues of the degree of pigmentation on
different areas of the body).
Carrying the models around with them (Psittacosaurus was
fortunately only the size of a large dog), the researchers documented
how both the gray and patterned variations appeared in different kinds
of light. The gray model acted like a kind of control to see the shadows
cast by the animal’s contours.
What they found was that the patterned model had the optimal
placement of light and dark to offer decent camouflage in shaded
environments, such as under a forest canopy. In more open settings,
however, the patterned Psittacosaurus stood out like a sore thumb…or a delicious meal for some hungry therapod.
Based on petrified trees and other finds at the site in China where this particular specimen of Psittacosaurus was unearthed, we know that it lived in, yep, a forest.
This is the first time countershading has been confirmed in the
fossil of a land-based animal. And, while the research was based on one
particularly well-preserved specimen of a single species, it takes us
one small step closer to knowing what the Age of Dinosaurs really looked
like.
By the way, if you read Dead Things regularly, you may have noticed
I’m a huge fan of artist renderings of dinosaurs and other extinct
animals. If you share my love, check out Paleocreations,
the home page of artist Bob Nicholls, who created some of the
Tacosaurus images in this post and is a co-author of today’s study. Full
disclosure: I have no connection, personal or professional, to Bob. I
just really appreciate a well-placed lightning bolt.
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