From: "Ahmed al-Mahasa Sha'ad" <am_shaad@hotmail.com>
If this happend in origin of birds it does NOT mean it MUST happen in every
linage of tree-living predators.
So the question is, what drove this to happen in birds and not in the other
tree-dwelling predators? What sort of circumstances, that are not present
today, would make therapod dinosaurs fly? Many of the animals that live in
trees today, or at least have some history of climbing trees, have fur,
which could be adapted over the course of time, to become something like
feathers. (Interestingly enough, the only flying mammal, the bat, uses skin
flaps and not modified hair). So far, however, this hasn't happened. I see
the evolution of hair into feathers to be much easier than the evolution of
scales into feathers. So, if we have a population of small therapod
dinosaurs living in the trees, fulfilling the role of, say, lemurs, why did
the dinosaurs start to fly, and why haven't lemurs taken wing?
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