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RE: Perching, climbing, roosting was Re: 11th specimen of Archaeopteryx

> Date: Fri, 11 Nov 2011 15:08:35 +1100
> From: tijawi@gmail.com
> To: dinosaur@usc.edu
> Subject: Re: Perching, climbing, roosting was Re: 11th specimen of 
> Archaeopteryx
> Anthony Docimo <keenir@hotmail.com> wrote:

> >> I'm afraid I don't understand the relevance of the flamingo. AFAIK,
> >> it doesn't perch or roost in trees. It spends its days (and nights)
> >> on terra firma.
> >
> > I think his point was a rebuttal of the claim that a bird's (or 
> > protobird's) feet are shaped by where it sleeps.

> Yes, but... if you are a theropod that walks on the ground, no extra
> pedal adaptations would be required to stand still on the ground,
> including when sleeping. However, if a theropod were to roost in the
> crowns of trees, I'd be surprised if it could "get by" with simply
> co-opting its terrestrial adaptations into an arboreal setting. If
> the animal walks on the ground, and sleep in trees, then the latter
> should foster some changes in pedal morphology. Simply having claws
> isn't enough.
 As was pointed out in this thread today (so you may not have gotten that post 
in your Inbox at the time I'm writing this), there are tonnes of tetrapods who 
have become arborean with minimal-to-no changes to their feet.  At the top of 
the list: snakes.  :)
> > By that logic, there shouldn't be anything (that hops or flies) living in 
> > deserts - that substrate actually moves.

> Yeah, but if you fall over in the desert, the fall typically won't
> kill or maim you. If you fall off a tree branch, it might be a long
> way down. 
 depends where the branch is.  some trees have their first sturdy branches over 
a hundred feet off the ground, while other trees have sturdy branches less than 
a foot off the ground.
> > Heck, there shouldn't be rock wallabies (gravity + uneven rocks + some 
> > rocks come loose) or thorny forest lemurs (gravity + thorn-
> > covered branches)
> These animals have specific adaptations to these lifestyles.
 While that is true, it doesn't render them immune to the dangers.  (those same 
lemurs, can still be impaled by those same thorns; rock wallabies can fall off 
a rock or die from a rock falling on them)
 It's like those desert fish...they were found in water over a hundred degrees 
F., yet they can be killed by being dropped into a tank of water that hot.
> Your
> statement underscores my point.
> >> Briefly, climbing up trunks and foraging within the crown promotes
> >> different adaptations.
> >
> > you have to get to the crown in order to feed in it.
> Birds fly up into the crown to feed in it. Certain birds climb trunks
> because they obtain food from the trunk, like woodpeckers,
> treecreepers, and nuthatches. The feet of these birds have special
> adaptations for trunk-climbing (and trunk-clinging).
 And if you can't fly, you have to cross the trunk to get to the crown.  ask 
any sloth or possum.