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Re: Possums (A Challenge)

on 5/3/05 2:51 PM, T. Michael Keesey at keesey@gmail.com wrote:

> On 5/3/05, don ohmes <d_ohmes@yahoo.com> wrote:
>> They are prolific, omnivorous and adapt well to urban
>> environments. That explains how they survive in their
>> present form, but does it explain why they don't
>> "improve", particularly relative to locomotion? They
>> don't climb well, run well, or even walk well relative
>> to other mammals. Granted, it is not possible for
>> selection to change a trait w/ zero variance, and the
>> difference between a fast and a slow possum may be
>> effectively zero relative to predator speed. But do
>> cast-iron stomachs and prolificity somehow mean
>> locomotive competence is disadvantageous? Even possums
>> have to compete for food.
> Developing greater speed, agility, etc. requires more resources than
> developing stubby little 'possum legs. An opossum with longer legs
> might be able to evade predators or catch prey more successfully than
> other opossums, but it would also need to eat somewhat more to
> maintain those larger legs. Apparently for opossums (and many many
> other species), this is not an advantageous trade-off. (See for
> yourself--they're doing just fine.)

Nobody seems to have mentioned that 'possums play dead as a defense against
predators instead of running away from them.  Or is this just an urban myth
devised to confuse Colorado-bound people like me who have never actually
seen one of these creatures?

>>Locomotion in possums could be vastly improved w/out
>>any re-allocation of relative body mass, and IMO, with
>>vast improvements in efficiency. Not longer legs, just
>>better. Possums even wobble when they walk. I have
>>seen apparently healthy, not-in-a-hurry possums fall
>>down trying to cross a dirt road. Observe an inbred
>>German Shepard with moderately severe hip problems, it
>>is the best analogy I know of.

Wow, that _is_ pretty sad.  Maybe it helps add to the unappealing, diseased
animal illusion.

~Tiffany Miller
         {"Look where all this talking got us, baby"}
                                             o    .     _______ ~~~~~
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               (http://www.deadraccoon.com)                 ~~~        /