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RE: Campbell's even crazier than a MANIAC? (archeopteryx climbing)
Quoting Tim Williams <firstname.lastname@example.org>:
>> Sim Kining wrote:
> > An eagle's talons are highly specialized for predation, so are the claws of
> > large cats,
>> neither seem to have a problem climbing around or perching in trees.
> Neither of these has claws *as* specialized as the sickle claw (and its
> supporting digit) of dromaeosaurids. Not even seriemas (cariamas).
Indeed. Eagle and cat claws tend to have circular or ovoid cross sections (as
do the claws of just
about any climbing, perching or grasping creatures). The narrow blade-like
sickle claws of the
larger dromaeosaurs would seem to be ill-suited to standing up to twisting or
> Yeah sure, maybe the sickle-claw of dromaeosaurids was used for climbing,
> branch-grasping, etc. But it clearly didn't evolve for this purpose. It
> sounds like a counsel of despair to argue that the sickle-claw was an
> arboreal tool - especially when there's no elongated, reversed hallux on the
> other side of the foot.
Given that those retractable swivel-toes seem to have been designed
intentionally to keep the
sickle claws clear of the ground, I also doubt they were regularly driven into
trees. Perhaps the
smaller, less blade-like claws of Dromaeosaurus itself (or Tro-odon for that
matter) may have
been used as climbing aids on occasions, but animals like Velociraptor or
preserved the claw tip as much as possible for use in hunting. It's best to
climb with a sturdy hook,
not a narrow blade.
It begs the question though; are the more 'advanced' dromaeosaurs with the
blade-like toe claws
decended from earlier climbing animals? Perhaps dromaeosaur ancestors had
stouter, chunkier toe
claws for climbing, and the lance-like toe claws of the larger and later
specialised forms - too specialised to continue being used as climbing aids.
How do the toe claws of juvenile Velociraptors compare to those of the adults?
If juvies have less
blade-like toe claws, then maybe they were used as climbing aids in juveniles,
but changed shape
as they matured to the point that adults were no longer able to use them for
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