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Re: La Brea...was: Extinction



-----Original Message-----
From: TRUETT GARNER <DINOBOY@worldnet.att.net>
To: sarima@friesen.net <sarima@friesen.net>; Tommy Tyrberg
<tommy.tyrberg@norrkoping.mail.telia.com>
Cc: jbois@umd5.umd.edu <jbois@umd5.umd.edu>; dinosaur@usc.edu
<dinosaur@usc.edu>
Date: Wednesday, March 29, 2000 9:46 AM
Subject: Re: Extinction


>
>
>> >Or do you simply attribute the whole of the Late Pliestocene/Holocene
>> >extinctions to human action?
>> >
>>Yes, though it is possible that climatic stress may have rendered some
>>animal population more vulnerable to human predation.
>
>Actually, I suspect the combination was a major factor.  Also some of the
>Late Pleistocene extinction in North America appear to have *preceded*
>human arrival here, at least based on the dating of finds in the La Brea
>Pits here in LA.  (Even though the peak extinctions occurred shortly after
>our arrival).
>
>


A quote from "La Brea Story" by Gretchen Sibley (1969), (OK, not a
scientific paper, but a phamphlet published by the Los Angeles County Museum
of Natural History),....
(referring to a hypothetical visit to "the pits" in the year 1492)...."About
eight thousand years earlier the climate had changed and lack of plant food
probably helped in the extinction of the imperial mammoth and sloths and
herds of bison and camel. The large flesh-eating cats and bears and wolves
vanished as their food disappeared."

There seems to be a discrepancy here, as you have stated that the climate
change apparantly preceeded man`s arrival, and this publication indicates
that the climate change took place about 8,500 years ago.

>Homo sapien occupation of North and South America has traditionally
>been associated with Clovis/Fulsom projectile points that date to 14,000
>mya .New evidence now puts the origin of these points in the southeast
>instead of western North America ,indicating a much earlier appearance here
>, for Homo sapiens. More and more the human occupation date in North and
>South America is being pushed back . A 14,000 yr. old Clovis site has been
>found in Peru and newer sites in North America seem to indicate a human
>occupation around 20,000 - 30,000 yrs. old . Given that proposed length of
>time , I find it quite feasible that mammoths , bison , camel and horse ,
>to name a few , were indeed hunted to extinction by this new clever ,
>well-armed predator for which they had no natural fear of , or defense .
>My $.02 worth,
>Regards ,
>Truett Garner
>