Re: "What did dinosaurs really look like..."

[Ronald Orenstein <ornstn@home.com>]

At 11:23 PM 20/08/00 -0500, max salas wrote:
> But we can make educated guesses based on what we know about them and what
> we know about our extant environment: For example, predatory animals are
> more modest in color than herbivores, this is more evident in birds than in
> everything else, and why is that?, well, they tend to live in flocks and
> showing off to get status or a mate is more important than being eaten.
> (numbers are a great defense for a species, if not for the individuals)
> check out parrots, chicken, peasants, etc.

Well, I don't want to comment on the colouration of the rural poor, but I'm 
afraid this isn't very accurate ornithology.  First of all, the statement 
that "predatory animals are more modest in color than herbivores" really 
doesn't hold up.  Although it is true that many frugivorous and 
nectarivorous birds are brightly-coloured, there are also numerous rather 
plain ones (eg many honeyeaters [Meliphagidae]).  Seed-eaters (which are 
certainly herbivores too) include many dull-coloured species (eg 
sparrows).  On the other hand, some predatory species such as pittas and 
bush-shrikes are extremely colourful (and I am incuding insect- and 
snail-eaters as predators here - they certainly aren't herbivores!).  Diet 
may be a very poor predictor of colour (compare the generally-dull Old 
World warblers (Sylviinae) with the generally-colourful New World warblers 
(Paruliinae).

Of course even dividing birds into predators and herbivores isn't too easy 
as many birds (eg woodpeckers) are omnivorous.

"Living in flocks" isn't much of  guide either.  Actually very few birds 
live in flocks year-round anyway, and flocking does not correlate at all 
with bright colour.  Many of the most brilliantly-coloured birds do not 
flock, and many dull-coloured species do.

In fact I am not sure at all that the life-styles of living birds, most of 
which occupy niches that must be quite unlike those of non-avian dinosaurs, 
can give us much of a guide to dinosaur colours.  Only a handful of birds 
are, for example, reasonably large and terrestrial.  Even among the 
ratites, male ostriches are brightly- or at least strikingly-coloured while 
rheas, which are quite similar ecologically, are not.

However, I am not much bothered by restorations that make at least a few 
basic assumptions drawn from birds - eg colour vision, dorsal 
countershading (given, for example, that almost all pelagic seabirds are 
black, white or grey in various combinations I see no reason why pelagic 
pterosaurs could not have been similar, though I do not recall seeing 
anyone paint a black-and-white Pteranodon) or bright colours or markings on 
such presumed display structures as the heads of oviraptorids or the 
casques of tapejarids.


--
Ronald I. Orenstein                           Phone: (905) 820-7886
International Wildlife Coalition              Fax/Modem: (905) 569-0116
1825 Shady Creek Court
Mississauga, Ontario, Canada L5L 3W2          mailto:ornstn@home.com