Re: Climbing dromaeosaurs?

[Betty Cunningham <bettyc@flyinggoat.com>]

Jaime A. Headden wrote:
>   Forgetting about woodpeckers walking up trees....
>   Based on a wolf-sized animal, there are several extant animals that
> climb regularly: young cougars and leopards and jaguars, some monkeys,
> young gorillas [this is not supposed to be a complete list]. 
>   All climb up trunks by splaying their forearms around the trunk
> either sideways or above their heads, and the hindlegs are below and
> under the body, more medial (closer to the midline) than not. For
> those with limited access to such wonderous sights, cats and squirrels
> climb the same way---mostly. Arboreal monkeys and everything else
> listed except gorillas have strongly curved claws with either a flat,
> round, or grooved ventral edge.

racoons and coatimundis all climb hugging the trunk and walking up with
the back legs.  Racoons can get up to 45 lbs.
I think the dynamics of how tree kangaroos (bipedal ancestry anyways) is
far more likely to show dromosaurid tree climbing dynamics than any
silly 'ol arborial quadraped would.

>   Dromaeosaurs have rounded surfaces to their claws, as Tom Holtz and
> others have pointed out before. The only abberant is *Utahraptor* with
> its laterally flattened blade.> 
>   Gorillas grasp the trunk much as we do (when we're not wearing
> cleats and using climbing ropes or such gear) and mostly use the
> strength of their legs to push up.

point one)
jaguars and gorillas both live in rainforests where food is commonly
found in trees-thus a reason to climb trees in the first place.

point two)
dromosaurs are usually depicted in drylands, canyons, arroyos, deserts,
etc.  What rainforests would that be?  What habitat did they live in
where so much of the food chain was EXCLUSIVELY in trees?  

point three)
Why would a large silly animal want to be in a tree in the first place?
If for predator avoidance that would mean the tree would have to be
larger than the largest predator likely to eat a jaguar-sized animal
(that would be a dang big tree-to avoid T rexes perhaps). If to hunt for
food either the jaguar-sized creature would need to be omnivourous (as a
gorilla is) to obtain the greatest amount of calories for amount of
calories spent in getting into the tree -or- would need to hunt and kill
large enough prey to return the high amount of calories spent in getting
into and hunting in trees.  On this last, WHAT is known that was large
enough to have a predator invest it's time in hunting in trees?  Mammals
were kinda small bites at the time.  Pterosaurs perhaps?  Hmm possibly. 
Other dinosaurs maybe- but um, why were THEY in trees then?

-Betty Cunningham