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Re: Campbell's even crazier than a MANIAC? (archeopteryx climbing)



Good point, but do any climbing vertebrates actually stick their claws well into the bark in the manner of crampons in ice? Couldn't they simply use the pedal claws to grasp the bark?

Dan

dinoboygraphics@aol.com wrote:
Sorry, I just got to this point in the discussion:

Crampons have points directed in two directions. A set of 8 or so
are on the bottom of the crampon for walking on icy / snowy surfaces. Two point forward from the front, to gain purchase on high angle or vertical surfaces, with the foot simply projecting into space. One can even stand with a single front directed point in the ice, is it is set well enough in the ice. But is such cases one is using ice axes or some such with one's arms.<<<

Um, crampon spikes are all essentially straight along the blade, for a very important reason: so you can get them out again! Unless the second pedal claw was particularly straight, it would be near impossible to pull out of the substrate, especially if you've moved yourself up relative to the original point of insertation. With manus claws this is less of an issue, since the axis of rotation is usually set below the point of entry even after pulling yourself up, but the toes have no such advantage, especially in non-splayed stiff-limbed maniraptorans. Trying to make Archie an adapted climber is an act in trying to make the facts fit a theoretical preconception on how flight should begin (if it even began in an Archaeopteryx-grade paravian).

My advice is to stick with skateboarding. <<<

They'd have to, as climbing vertical trunks would be right out.


Scott Hartman Science Director


Wyoming Dinosaur Center 110 Carter Ranch Rd. Thermopolis, WY 82443 (800) 455-3466 ext. 230 Cell: (307) 921-8333

www.skeletaldrawing.com


-----Original Message-----
From: Dan Chure <danchure@easilink.com>
To: david.marjanovic@gmx.at
Cc: DML <dinosaur@usc.edu>
Sent: Sun, 7 Sep 2008 6:20 pm
Subject: Re: Campbell's even crazier than a MANIAC? (archeopteryx climbing)



I'm not sure what you mean by side-to-side. Crampons have points directed in two directions. A set of 8 or so are on the bottom of the crampon for walking on icy / snowy surfaces. Two point forward from the front, to gain purchase on high angle or vertical surfaces, with the foot simply projecting into space. One can even stand with a single front directed point in the ice, is it is set well enough in the ice. But is such cases one is using ice axes or some such with one's arms. My advice is to stick with skateboarding. Dan David Marjanovic wrote:
Setting aside true arboreality for the moment - how well would they
>> be have been able to use their claws as crampons for ascending >> trunks, rocks, whatever?
Don't crampons work side-to-side? Sickle claws worked top-down and >
probably had a cutting edge. They were not round in cross-section.

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