Re: Numbers of Dinos???

[Stan Friesen <swf@ElSegundoCA.NCR.COM>]

>From: sugarman@cerf.net
 > 
 > Does anyone have an idea how many T-Rexes there were?  Are we looking at a 
 > population of a few or 
 > are we looking at a situation where there were literally hundreds of 
 > thousands scattered everywhere?
 > Were dinos common?  

Hundreds of thousands alive at one time is *extremely* rare.
Most uncommon animals have populations in the low millions.

As to actual numbers, no we really don't know.  However, based
on specimen counts, T. rex was rather uncommon (about a dozen
specimens, not counting teeth).  On the other hand, Triceratops
was *very* common, with over thirty skulls, and many more individual
bones.  Edmontosaurus and Anatotitan have similar specimen counts.

This is pretty much what is expected, the herbivores are common,
the large carnivores are relatively uncommon.

The large numbers of the large heribvores suggests an actual
abundance approaching that of the American bison, or the East
African antelope.  If so, then T. rex may have been about as
common as lion or hyaena packs (perhaps one T. rex in area that
would sustain a single pride of lions)

This adds up to alot of individuals.  The species ranged at
least from central Alberta to northern Utah, and from the edge
of the Rockies east past the Black Hills.  This is a great many
square miles.  [T. rex *may* have ranged as far north as the
northern Alaska, and as far south as the Mexican border, but
that is based on fragmentary specimens, and is uncertain].


Based on certain assumptions, I once estimated that the total
number of Triceratops that ever lived (over the whole several
million years of their existance) exceeded a trillion individuals.
[This gives you an idea of the sampling rate: some 50 to 100
individuals out of a couple trillion].

swf@elsegundoca.ncr.com         sarima@netcom.com

The peace of God be with you.