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Re: Tyrannosaur age-population distributions



Quoting Phillip Bigelow <bigelowp@juno.com>:

On Sun, 16 Jul 2006 08:46:02 -0400 Graydon <oak@uniserve.com> writes:

the breeding pair doesn't last long enough to raise their own offspring, so how does the pack form?


Pack-forming may still have been an important part of _T. rex_ behavior,
but it may have occured only part of the year.  Alternatively, pack
behavior may have been the norm for most of the year, except for a short
period where mate selection was taking place (when all of those injuries
in the adults may have accrued).

Perhaps the key word is 'most' adults seem to have died soon after reaching sexual maturity. This might indicate a wolf-like pack structure with a single breeding pair, or possibly even a lion-like social structure with a single dominant animal. Once offspring get old enough to become reproductive competition, one sex (depending on whether males or females were the dominant animal) may have been forced out of the group to fend for themselves.


Death rates for these animals may well have been high (as I imagine mortality rates for male lions are once evicted from the pride). The dominant breeding pair, however, may have faired much better - until eventually over-thrown.

SNIP

In the juveniles?  Maybe.  According to the new paper that came out just
last week, juveniles led relatively "safe" lives up to about age 20 (body
bags for the juvies are almost non-existant).  So perhaps the youngun's
didn't hurt each other.

Or they readily ate their siblings' corpses, preventing them being fossilised.

--
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Dann Pigdon
GIS / Archaeologist         http://heretichides.soffiles.com
Melbourne, Australia        http://www.geocities.com/dannsdinosaurs
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