Of course, the Bedouins had all kinds of other superstitions about white
and black markings, hair growth patterns, etc as indications of
performance ability, loyalty, and good or bad luck. For instance, the
Bedouin considered a horse with no white on it to be bad luck. And they
also had beliefs about what colors/coat patterns etc. should be crossed
with each other to produce .... They also considered a chestnut with a
"flaxen mane and tail" to be an indication of impure breeding.
I don't know whether these different traits were linked to the
color/coate patterns, etc. or whether since both color and these traits
are heritable, it is merely a case of what my statistics professor called
"block booking" (e.g. just because tall people have bigger feet than
short people--in general--doesn't mean that big feet causes people to be
tall) It is the difference between correlation and causation. (The
technical term for Sandy's comment about the chicken and the egg thing).
However, if you look at thoroughbreds, there does seem to be some
validity to the old bays are stayers and chestnut are fast (and grays are
neither). Statistically speaking, there is a disproportionate number of
chestnuts who are winners and a disproportionate number of grays who are
losers. This takes nothing away from Native Dancer and Spectacular Bid,
two absolutely fantastic grays.
But it could explain why you don't see many gray thoroughbreds.
It could also be because none of the main arab/barb stallions used in
founding the throughbred (the Darley Arabian, the Godolphin Barb--some
people call him the Godolphin Arabian--and the Byerly Turk--some people
suspect that this horse was actually an Akhal-Teke) were gray. These are
not the only oriental horses that were used in founding the thoroughbred,
but they were the most influential (there is another one, which actually
had more influence than the Godolphin Arabian, but nobody's ever heard of
him--even I can't remember his name--but he wasn't gray either).
It is possible that there are so many grays in endurance today, because
gray was a very fashionable color for arabs in the mid 80's--which would
make them just about the right age right now. And the reason they are
becoming less prevelant is because gray is no longer fashionable--it went
out in the early 90's.
The way I see it, there is little evidence (or too much conflicting
eveidence) to suggest that success in endurance is in any way a function
of color (i.e. all things being equal, one color is better than another),
so to answer the original question...
...All other things being equal, pick the one that you think is the
prettiest color. For me, that's the chestnut, and I already explained my
totally irrational prejudice about that.
kat
p.s. It has been my experience, that rarely is it ever a case of all
other things being equal. So if I were truly reasonable, I would ignore
color entirely.