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Did Feathers Evolve for Dispaly? We Still Don't Know!
First of all, I will say that Benton et al.'s new work on the probable life
coloration of _Sinosauropteryx_'s plumage is fabulous, and makes history as the
first time the life coloration of a dinosaur (not just patterning, but
coloration) has been worked out. Magnificent. So big congrats to Benton and his
But the point of this post is really something else - I am addressing the claim
that this discovery provides convincing evidence that feathers (in this post I
will be including protofeathers under the blanket term "feathers") initially
evolved for display. Here are the relevant quotes from the news story Tom
“Our research provides extraordinary insights into the origin of feathers. In
particular, it helps to resolve a long-standing debate about the original
function of feathers – whether they were used for flight, insulation, or
display. We now know that feathers came before wings, so feathers did not
originate as flight structures.
“We therefore suggest that feathers first arose as agents for colour display
and only later in their evolutionary history did they become useful for flight
As the paper does not seem to be out yet, these quotes are all I have to go on,
but from them, Benton seems to be saying that the fact that _Sinosauropteryx_
appears to have been vividly colored in orange and white in life, this supports
the hypothesis that feathers arose as display devices. This is what I take with
issue with. For one thing, we don't actually know that _Sinosauropteryx_ itself
used its feathers in display, we have no evidence for this, as orange and white
banded coloration would serve purposes of camouflage just as well. Second, even
if _Sinosauropteryx_ itself *did* use its vivid color patterns in display, that
the animal had striking plumage in no way even begins to support the hypothesis
that feathers themselves evolved for display, or at least not any more than
that the bright and vivid plumage of many modern birds provides evidence for
such. And the fact that many modern birds possess bright and vivid plumage has
been known since, well, ever since bipedal Holocene apes first looked at birds,
and long before evolution in the first place was recognized, let alone when the
question of what bird feathers originally evolved for began to be pondered at.
So the point is that a vividly colored_Sinosauropteryx_ does not add any *new*
evidence to support the display hypothesis that we didn't have before.
Take this other example, if you will - Zebras possess extremely bold
black-and-white striped fur coloration, so that predators examining the herd
have a difficult time differentiating one potential target from another; in the
eyes of the color-blind mammalian predator, individuals and their outlines
disappear in a sea of stripes. Does this provide evidence that mammal fur
initially evolved to confuse predators? No, of course it doesn't. The situation
with _Sinosauropteryx_ and the initial evolution of feathers is pretty much the
Hence the title of my post - did feathers evolve for display? Maybe. Maybe not.
(My own personal opinion is 'not', but that digresses, and matters little
anyway.) The point is that the hypothesis that feathers initially evolved as
display devices is really no more robust today than it was yesterday, or the
day before that, or the day before that.
So there it is. We still don't know.
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