Re: Tyrannosaur age-population distributions

[Dann Pigdon <dannj@alphalink.com.au>]

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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