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Re: AW: Heterodontosaurid with protofeathers



Quoting Erik Boehm <erikboehm07@yahoo.com>:

> --- On Thu, 3/19/09, don ohmes <d_ohmes@yahoo.com> wrote:
> > More seriously: color often does not matter as much as
> > silhouette and texture in camo, even as used today. Deer
> > camo works in dayglo orange, as example. Not something a
> > sniper would choose, of course.
> 
> Most mammals are colorblind, with primates having re-evolved a pigment
> sensitive to another wavelength of light.
> 
> We should assume Dinosaurs had an excellent sense of color, as birds do
> today, and that dayglo orange would most definitely stand out as much to a
> predator or prey as it does to us (but not colorblind deer).

Modern birds and reptiles often have gaudy colour patterns, despite their 
predators (other birds 
and reptiles) being able to see colours.

Bright colour patterns are certainly noticable in open areas (where most sexual 
displays take 
place), but are less noticable in partial shade or dappled sunlight, where 
identifying things by their 
colour patterns alone can be difficult. Alternating colours (bright or not) can 
help to break up the 
outline of an animal in dappled sunlight.

Tigers are a good example. Alternating patterns of black and bright orange are 
very noticable to us 
colour-visioned humans when a tiger is in open terrain (especially contrasted 
against green grass), 
but once they move into dappled sunlight they all but disappear. Tigers try to 
avoid strolling about 
in the open when they're stalking prey, since keen-eyed monkeys and birds tend 
to spot them 
easily and give off alarm calls. However given enough cover, a gaudily 
patterned tiger can sneak 
it's way into ambush range despite the dozens of colour-visioned tattle-tales 
in the area.

-- 
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Dann Pigdon
GIS / Archaeologist              http://geo_cities.com/dannsdinosaurs
Melbourne, Australia             http://heretichides.soffiles.com
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