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Re: AW: Heterodontosaurid with protofeathers
Quoting Dora Smith <email@example.com>:
> Hair is such a good idea that something like it evolved at least
> twice; in mammals and in therapod dinosaurs (maybe all dinosaurs, maybe
'Hair' is a fairly specific term that really only refers to mammalian
If you mean integumentary structures in general, then they could have evolved
at least three
times, depending on whether or not dinosaurs and pterosaurs had a fuzzy common
Possibly more than three. There's no reason to assume that fur evolved just
mammals, let alone amongst dinosaurs.
> It would have been in response to - the weather.
It's clearly not that simple, since plenty of non-fuzzy animals are also
exposed to the weather.
Insulatory integumentary structures are only useful in endothermic animals,
downright maladaptive in ectothermic beasties.
In fact it could be argued that insulation is *mandatory* if you're
temperature fluctuations on a regular basis (the 'naked mole-rat clause'), and
are below a certain
size threshold (the threshold itself being determined by the extremity of the
endured). I'd be surprised if *any* small non-burrowing or non-aquatic
endotherms at any time in
the past didn't have some sort of insulatory integument.
GIS / Archaeologist http://geo_cities.com/dannsdinosaurs
Melbourne, Australia http://heretichides.soffiles.com