Re: On predation.

David Froehlich (
Sat, 28 Oct 1995 11:15:45 -0500

On 27 Oct 1995, H. M. Hubey wrote:

> >> With rivers and lakes drying up and restarting up many times
> >> over millions of years, they'd have to be reinfested everytime.
> >You really don't know anything about geology do you?
> IF you're trying to be funny, don't give up your bonegazing yet.

Actually I was pointing out that you do not know anything about geology
and your statement was incredibly ignorant. The distribution of surface
water is controlled by two factors, local or regional precipitation and
the movement of water underground (I am summarizing for non geologists,
it is actually somewhat more complicated). The movement of water
underground is controlled by the geology. If you have surface runoff
then it is controlled by gravity. If you have a change in climate to
produce runoff in places where it has not existed recently then that
water will flow downhill to base level (sea level in most places).

> Example:
> ONly a couple of years ago someone looking at a LAndsat
> photo noticed that at one time there was a large
> river running through the Arabian peninsula. That means
> that places like Rhub Al-Khali were green at one time.
> Suppose the weather patterns change again and the river
> starts to flow. Now tell me how long it would take before
> the damn crocs would infest SAudi Arabia.

This just demonstrates your ingnorance. Sure there could have been
rivers there (in fact, as you point out, there is empirical evidence of
such). The question you fail to ask is "where is this water going". In
the cases you note, all of the rivers are flowing into existing bodies of
water (Indian Ocean for instance). It has already been noted that
crocodiles will travel in the open ocean. My guess is that given such a
situation you envision, crocodiles would probably colonize this nice new
environment in a few short years (100's to 1000's of years).

David J. Froehlich Phone: 512-471-6088
Vertebrate Paleontology Laboratory Fax: 512-471-5973
J.J. Pickle Research Campus
The University of Texas, Austin, Texas 78712