[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
RE: Campbell's even crazier than a MANIAC? (archeopteryx climbing)
Jeff Hecht wrote:
> Flight originated with feathered theropods who used trees (or some other
> elevated objects) as hiding
> places for nests. They didn't live in the trees - they just nested there.
> Partial wings helped them flutter
> down without injury.
A nice example of this sort of behavior is the secretary bird. This
long-legged raptorial bird spends most if its time on the ground (including
when hunting), but roosts and nests in trees.
A possible problem for the idea of nesting in trees being a pre-flight
character is that I thought I read somewhere that this behavior is actually
quite derived for birds. I wish I could provide details, but (once again!) I
can't remember the paper.
> That strategy might have worked best for a small Microraptor-like animal,
> which could dash up the tree
> or into the shrub when danger threatened, then get back down quickly when
> danger left.
Yes, a great many small mammals head up trees when a large (or larger) predator
comes around. I wonder about this for small theropods, because the best
strategy in response to approaching danger might simply have been to run away.
This is especially true when an especially large predator was coming its way:
Although the crowns of trees might provide a good hiding place, it also runs
the risk of leaving the small theropod stranded at eye-level with the predator!
> I doubt that was the only advantage -- once feathers started to evolve to
> larger size, they probably
> offered more advantages including, eventually, powered flight.
Indeed. Exaptation probably played an important role in the first appearance
of feathers, as well as later refinement(s) (like enlarging them).
See how Windows Mobile brings your life together—at home, work, or on the go.