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Re: Dromeosaurid behavior........Pack hunting! (long)



At 10:00 AM 5/1/99 -0500, megaraptor wrote:
>
>
>"Thomas R. Holtz, Jr." wrote:
>
>> At 04:10 PM 4/28/99 -0500, "Megaraptor" wrote:
>> >I'm glad someone agrees with me.  There are no real disadvantages to the
>> >pack hunting life style.
>>
>> How about:
>> 1. Competition with your siblings for food resources and mates.
>> 2. Large necessary "home range" than an individual.
>
>Wouldn't these actually be advantages instead of disadvantages? I mean,
>the strongest do survive, especially in carnivorous animals such as most
>predatory birds.
>
No.  This is based on a misunderstanding of how selection works.  The above
will always tend to reduce reproductive success.  Even in predatory birds,
when there is sufficient food both hatchlings can be reared successfully.
So competition *is* limiting reproductive success, even there.  The reason
a second egg is hatched is a "spare" in case the elder dies for some reason
- otherwise loss of a hatching would mean loss of entire season's reproduction.

>It doesn't make sense to me that being opportunistic while hunting is a
>advantage, it's more like a disadvantage.  During the times of the year
>that most of the herds moved south for the dry season the dromeosaurids
>would have likely followed them.
>
Why would dromaeosaurids do something that no living predator does?
Between home range requirements, defense of territories, and issues with
respect to care of young, no large predator today is able to move around
the way some migratory herbivores do.

A prime example is the Serengeti.  Here the major herbivores (gnu, zebra,
and gazelles) all migrate in a vast circle, following the rains around the
region.  NONE of the carnivores follow these herds, despite the dearth of
large game in the dry season in each locality.  Lions, wild dogs, jackals,
and hyenas all remain in their home territories year-round.  They just
synchronize reproduction with the arrival of the herds, tending to wean the
young when the herds leave.  I cannot imagine a more extreme case - from
millions of large herbivores per square mile to essentially zero off
season, and yet the carnivores *stay* *put*.
>
>>
>> In Nature it is very rare for a single strategy to be "The Best".  That is
>> one of the reasons for the vast diversity of life now and in the past.
>
>I don't know what you meant by "a single strategy being 'the best'"

The point is that different approaches to getting sustenance are effective
in different situations.  Life is a vast, complex, game of
scissors/paper/stone.

--------------
May the peace of God be with you.         sarima@ix.netcom.com