Prosimian arboreal quadrupedalism-tree climbing...

Tom Dunlap

Tom Dunlap

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I was doing a little research for a class and found this article. I felt a bond with the quads that were studied.

Tom

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Source: American Journal of Physical Anthropology, Annual 2003 p200(2).


Title: How does branch stability affect prosimian arboreal quadrupedalism?
Author: N.J. Stevens Author's Abstract: COPYRIGHT 2003 Wiley-Liss, Inc.

Current views on primate origins suggest that the initial divergence of primates was related to adaptations for foraging and feeding on small terminal branches. One of the challenges of such a habitat is that the supports are frequently compliant and unstable. Thus an arboreal quadruped must contend with the fact that the supports on which it rests, feeds and travels may move beneath its feet. While researchers have commented on effects of branch stability upon energy costs, foraging strategies, and resting postures, fewer studies have attempted to identify the kinematic mechanisms primates use to maintain balance while walking on unstable supports (Stevens et al. 1999).

This study examined the effects of branch stability in a sample of cheirogaleids, lemurids, and lorisids. All are arboreal quadrupeds, but differ in body size and shape. Limb posture was recorded during locomotion on fixed and compliant supports, and joint angles and gait patterns were examined.

The five species examined in this study all adopted a suite of accommodations to unstable supports. These included bringing the center of mass closer to the branch and using larger forelimb and hindlimb excursions. This was accomplished by more protracted forelimbs at touchdown and more retracted hindlimbs at lift-off. In addition, hindlimbs maintained relatively longer contact times on unstable branches. Taken together, these consistent patterns suggest that animals of diverse body shapes may use markedly similar strategies to cope with branch instability.

This work was supported by the Sigma Xi, L.S.B. Leakey, and National Science Foundations.
 
Sorry, but I've been raised in a country where everything is dumbed down to a 5th grade reading level. It has been so long since I've seen writing like this that I cannot even understand it. Do we have a translator available?
 
Re: Prosimian arboreal quadrupedalism-tree climbin

RJS,

There are any number of on-line dictionaries available. :)

Thepicture that I had in my head was of the same researchers following crews of arbos around to see if the research parameters fit for how arbos move around in the crowns. I think that they would have concluded that the climbers who were skilled enough to work the tips of the limbs were the ones that were the better climbers. Since money is what feeds arbos, the ones who "feed" at the branch tips will be thw best nourished in the same way that their subjects ate the good food at the branch tips.

Tom
 
Re: Prosimian arboreal quadrupedalism-tree climbin

Tom, I think you're right about the arbos getting to the tips being the better arbos. Let's consider the rest of your statement from a Darwinian stand-point...

The current state of things have it so that it is the customers that feed the arbos their food ($). I think most customers are impressed and pleased if they step outside and see a large pile of brush and the trees stripped up pretty high...it looks more "clean."

These customers will be so pleased that they will tell their neighbors to feed the arbo, as well.

As long as customers are not properly educated, the unskilled arbos will keep getting fed. The customers come out and look at the tree done by the "better" climber and see that it looks pretty much the same (to the untrained eye). The customer will be less likely to want to feed you again!

So Darwin has failed us. The more highly evolved species is less able to proliferate (is that maybe a $25 word?). As long as the current environment permits non-tip trimmers, it will be tough for us.

For us to flourish, we need to either find an environment where there will be educated customers to feed us, or we can create our own (educate the customers ourselves!)

love
nick
 
Re: Prosimian arboreal quadrupedalism-tree climbin

Geez. This makes TWO posts by Lovey that I must agree with today. Excuse me while I go slice open my wrists with a dull Zubat.
 
Re: Prosimian arboreal quadrupedalism-tree climbin

Nick,

You've taken the view that its the customer who is setting the value of the job based on the work of the climber. The work/pay is based on the pile or brush. An interesting thesis.

The angle I was looking at was to look at how the climbers got to, ..." foraging and feeding on small terminal branches" Since there is more food value in terminal growth, the better adapted climber would be able to keep fit with less work. Since we know that working in the tips is better for the tree, our reward, maybe not montary, will come by being good enough climbers to work effeciently out there.

Tom
 
Re: Prosimian arboreal quadrupedalism-tree climbin

No, you're forgetting that tree time and Darwininan evolution time are much slower than people time. As more arborists prune trees correctly, more people will see the long-term results versus the lack thereof from the strippers and the toppers. Certainly I agree, though, that we should hasten this process by educating as many people as possible.

If you're patient enough, the dinosaurs die out. It's just too bad that, in this case, the giant corpses they leave behind are someone else's.

Keith
 
Re: Prosimian arboreal quadrupedalism-tree climbin

"You've taken the view that its the customer who is setting the value of the job based on the work of the climber. The work/pay is based on the pile or brush. An interesting thesis."

Maybe carry a loaded trailer to each job so as to have a stock of wood on hand for appearance's sake.
 
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