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Re: T.Rex Feather Skepticism
On Wednesday, September 14, 2005, at 10:48 PM, frank bliss wrote:
The cute tyrant looks like a good prey item for a hungry Upper
Cretaceous mammal to me. Interesting that almost all domesticated
barnyard birds are fluffy and cute from the egg....
Most domesticated barnyard birds are largely terrestrial, precocial
forms (and generally galliform birds, specifically). They are 'fluffy'
because they must be capable of thermoregulation soon after birth. The
reason we tend to domesticate such birds is probably several-fold,
1) They have large, light-fiber based pectoralis major muscles (good
for short, sprinting flights), and we find this yummy.
2) They live largely on the ground (which is related to point number
1), which makes them easier to contain and raise.
These traits happen to be somewhat correlated with precociality (though
this is, in part, a phylogenetic effect). Thus, these traits are
correlated with fluffiness. Other than the phylogenetic constraints,
ground-living birds that are poor sustained fliers probably tend to be
precocial, because the offspring are under pressure to leave the nest
early, and they presumably utilize a food source available without
flight (since the adults are poor sustained fliers).
The exceptions to much of the above are domesticated waterfowl; in that
they are strong sustained fliers. However, they still feed on the
surface (water, instead of terrestrial surfaces), and they still nest
on the ground in accessible regions (and they are considered to be
sister taxa to galliforms, in many analyses), so it is not surprising
that they, too are precocial.