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Re: Phorusrhacids killing large mammals in National Geographic Channel
On Wed, Jul 29, 2009 at 02:34:50PM -0300, Augusto Haro scripsit:
> Perhaps parrot beaks primarily represent a nut-cracking device, as you
> say. There are many other birds, of which I mostly mind passeriforms,
> which possess thick beaks, but not so curved, which seem to break
> relatively big nuts,
"nut" is not a generic structure!
Thick-billed seed eating passerines, such as finches and cardinals, are
cracking seeds that have a relatively thin outer husk and split
naturally into halves.
The big macaws have evolved to eat Brazil nuts, which are multi-layered
and very tough; see