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Re: group hunting (was Scavenger vs. Predator Argument)



To Bill , etc:


-----Original Message-----
From: Bill Adlam <wa105@mead.anglia.ac.uk>
To: dinosaur@usc.edu <dinosaur@usc.edu>
Date: Thursday, February 26, 1998 1:26 AM
Subject: group hunting (was Scavenger vs. Predator Argument)


>Jack Conrad wrote:
>
>>                                                               ...It
>>should also be noted that lionesses do the majority of the hunting <
SNIP!!!.....

>
>The gracile and robust morphs probably represent different sexes, and the
>robust ones are probably females.  I would guess the difference in size and
>strength was similar to that in lions, but with the females bigger.  I'm
>sure someone on the list is familiar enough with both to correct me.
>
>
>T. rex presumably laid numerous eggs which produced small hatchlings, so
the
>breeding potential of a group would depend more upon the number of males
>supplying meat than the number of females laying.  This is one situation
>where a polyandrous mating system is evolutionarily possible, but it is
>possible that only a few of the strongest males mated.  The others would
>have to be closely related to make it worth their while to hunt.

>Speculating beyond the evidence, it's possible that T. rex males formed
>prides led by one or a few females.  The strong females would defend
>territory, but the faster and stealthier males would make more effective
>hunters.


SNIP!!!!

    I agree that the likelyhood exists that there is sexual dimorphism in
_T. rex_ - there seems to be two distinct forms.   Most would agree that the
larger forms are female (this seems to match up with similar patterns in
many birds, etc.).

    My understanding is that the number of offspring of _T. rex_ per season
(or per nest - if you wish) is unknown.  The only reference that I recall is
a suppossed _Tarbosaurus_ nest  - with two rather large eggs in it found in
China within the last 18 months.

    (That sort of shoots down some of your sceme - sorry).

    Allan Edels


>
SNIP!!!!
>Armed with this theory I predict a strongly male-biased sex ratio in T.
rex.
>And sure enough, there is.  It also explains why Sue suffered more injuries
>than males: fighting between females over the large resources of a pride of
>males would be much more serious than a squabble between closely related
>males over how many times each will mate with one female.
>
>I won't be surprised if this is shot down in flames.
>
> All the best,
>
> Bill
>