SPECULATION (WAS Re: Jurassic Park)

[Brian Franczak <franczak@ntplx.net>]

Pete Von Sholly wrote:
 
> Yes, and further, the point I wished to make is that as far as I know, it
> is not an "almost" certainty that Velociraptors had fur or feathers.  Nor
> is it REAL simple to know things like that.  If this list fills an
> educational role in any way, I think it's wrong to spread speculative ideas
> as though we really know things that we don't know.  People could "learn" a
> whole lot of hooey that way.

Pete is absolutely right in his comments, but there is a caveat.
Speculation is a valid -- even necessary -- part of scientific inquiry.
Without it, we could never move past what was tangible, the hard
evidence of our discoveries. But we must remember that there is a vast
difference between wild speculation and reasoned speculation. Claiming
that _Velociraptor_ was feathered is not unreasonable -- even without
proof positive --  and as long as it is presented as speculation and not
established fact it is as valid a representation as any. However, since
*no* skin impressions from _Velociraptor_ have ever been discovered, an
artist restoring this dinosaur with scaly integument should therefore be
required to make the same disclaimer, no? There is at present no proof
either way, so why should one viewpoint be exempt and not the other?
Lacking hard evidence, *both* are speculative, and until such evidence
is found (if it ever is) both must be accepted as valid. 

At the other end of the spectrum is the mention of a "feathered"
_Tyrannosaurus_. To my knowledge, no one in the paleontological
community -- either scientists or paleolife artists -- has ever
suggested that an adult _T. rex_, because it is a maniraptoran theropod
closely related to birds, should be depicted as feathered. This is
unreasoned speculation of the wildest kind, and completely unsupported
by any scientific basis. (And since there is also a small sampling of
skin from a "tyrannosaur" that shows a distinct pebbly texture -- as is
the case for all large theropod skin samples -- the point is moot
anyway.) But *small* theropods, on the other hand, are another matter
altogether. There is at present only one small theropod known to show
integument: _Sinosauropteryx_. And it is "feathered", not scaly. Only
two specimens of _Compsognathus_ even exist; that neither of them
exhibits a "feathery" integument is not proof that they *weren't*
feathered, since there is no evidence of a scaly-textured skin either.
And remember, two specimens of _Archaeopteryx_ likewise show no evidence
of pelage (one was misidentified for years as another specimen of
_Compsognathus_, the other as a pterosaur). So, is it speculative to
show other small theropods than _Sinosauropteryx_ as "feathered"? Yes,
it is. Is it wild or unreasoned speculation? No. No more than it is to
show them as scaled, since there is at present no proof for that
condition either. (And don't forget to ask *why* a small theropod --
*any* small theropod -- would *need* to be "feathered" instead of
scaled. The discussion about thermoregulation is far from over.)

All this brings up an interesting point about speculation, particularly
as it applies to restoring dinosaurs. If we follow the line of thought
that it is unreasonable speculation to restore animals that we have
incomplete evidence for (i.e., lacking "skin texture") based on what we
know from other forms (closely related or not), then almost *every*
restoration of a dinosaur is nothing more than wild speculation. To wit:
Do we have skin samples for every single genus/species of dinosaur? Are
these samples complete in every detail, giving an unbroken skin map from
snout to tailtip? Hardly. So how is it possible to restore most of these
animals without *some degree* of speculation? Do all related forms, such
as ceratopians, have the precise same pattern of scales? What about
hadrosaurs, sauropods, or big theropods? Again, hardly. But is it not a
reasonable assumption that they resembled one another, in general if not
in every specific? Worse, what about color? Even drab grays and browns,
with no patterns, stripes, or spots is completely and totally
speculative, since there is no evidence for color whatsoever. Yet has
that ever stopped any paleolife artist from rendering a dinosaur in
color? This is in some ways the *wildest* speculation of all, yet there
is sound reasoning behind it as well: Crests, frills, and other display
structures, sexual dimorphism, and large optic lobes are all good
evidence for seeing and displaying colors. But *what* colors? In what
patterns? Should we stop restoring dinosaurs altogether because we can't
answer those questions with 100% fidelity? That's where (reasoned)
speculation comes in.

The preceding example shows that there is, I think, a line to
speculation that we must sometimes cross, like it or not. To be a
complete slave to "What We Know" is to deny the unbounded human capacity
for asking, "What if...?" Sometimes we need to move beyond "What We
Know" in order to move forward. Sure, mistakes will be made, and often
it *is* hard to dispel those ideas once they've become entrenched. But
do we still believe that dinosaurs dragged their tails, or that
sauropods were bound to the swamps by their vast weights, or that no
theropod could possibly *ever* be "feathered"? These ideas, once very
deeply entrenched, have now been dispelled; we've moved beyond them, no
matter how beloved or how staunchly supported they were. With
speculation, it's just important to learn the difference between the
wild, unsubstantiated kind and the kind that is more reasonable. It's
tricky, but that, ultimately, is how we learn and advance.

Brian (franczak@ntplx.net)
http://www.paleolife-art.com