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Re: Nesting strategies (was Big = Old = Advanced?)



Bryan R. Stahl writes;

>But would it follow the wolf - coyote pattern, or would it take an African
>style pattern, i.e. lion - jackal, hyena - cheetah, or lion - hyena?  The
>wolf - coyote pattern would seem to apply to the different species of
>tyranosaurids,  with the smaller being driven into more marginal areas by
>the larger.  The African pattern seems closer to the dromeosaur -
>tyrannosaur idea.  The idea being, would they directly compete like lions
>and hyenas(which ever side has the advantage driving the others off), would
>the dromaeosaurs scavenge like jackals, or would the tyrannosaurs plunder
>the dromaeosaur kills like hyenas and lions do to cheetahs?

To start off, let's define each of the patterns you recognize.  The lion-jackal 
pattern is where the smaller species tends to come in after the big one has 
finished with it's kill.  The hyena-cheetah pattern is the exact opposite, 
larger species stealing the smaller species kill, so let's consider this to be 
the flip side of the same coin.  The lion-hyena pattern deals with two species 
that are evenly matched in size, strength, and power.

In a Cretaceous setting, the hyena-cheetah pattern would fit best with 
tyrannosaurs and dromaeosaurs.  The smaller theropods would most likely be 
driven off a kill by the larger theropod.  I'm not sure what, if any, effect 
that pack living would have on this pattern, but I suspect that even a good 
sized flock would be driven off by the tyrannosaur (is it safe to assume that 
there was an inverse relationship between the size of the pack and the size of 
the species?).  The way that the lion-hyena pattern would come into play is if 
there were two species of tyrannosaur, or a tyrannosaur and an albertosaur, 
living in the same area.

I suspect that each species of the larger theropod, or each individual/pair 
bond 
(depending on your viewpoint), had a distinct home range that could be easily 
defined.  How the smaller theropods related to this is anyone's guess.  The 
smaller theropod could pose a serious threat to the larger theropod's chicks, 
and so the smaller ones would be driven off.  Then again, if the food supply 
was high enough, the larger theropods might tolerate the presence of the 
smaller ones (especially the troodontids).  There is also a question of whether 
the two species operated under different niches, which would cut down on how 
they related to each other; perhaps some dromaeosaurs specialized in 
scavanging.  

This is where paleontology gets really tricky: when we try to interpret the 
ecology of the time.

It would be really interesting to see if we can interpret home ranges from the 
fossil record.  Does anyone know if larger theropods are found nearby areas 
where the smaller ones have been found.


Shalom,

Rob Meyerson

***
"Keep your stick on the ice."
        -Red Green