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Re: Jurassic Park 4: Electric Boogaloo



--- Vorompatra@aol.com wrote:

> In a message dated 2/11/05 3:05:31 AM Eastern
> Standard Time, 
> DinoBoyGraphics@aol.com writes:
> 
> << To some degree you are right, especially in terms
> of the behavioral 
> flexibility that such social groups display.  But
> Nile crocodiles have been reported 
> to engage in what appears to be cooperative herding
> of fish schools towards 
> ambushes by other crocs.  Although more stereotyped
> in their response, schools 
> of fish exhibit excellent coordination of group
> movement, with even less 
> intelligence than crocodillians have.  So while
> packs of non-avian theropods may 
> not be expected to show the same level of behavioral
> plasticity that modern 
> placental mammals display, the brain requirements
> for coordinated (if stereotyped) 
> group behavior seems to be well within their grasp.
> >>
> 
> Fair enough, although the crocodile activity seems
> dubious....

+++++++++++++++++++++++++++

This phenomenon among crocs is actually well
documented.

From: Pooley, A.C. "Food and Feeding Habits" in
Crocodiles and Alligators, 1989. Ed: Charles A. Ross.
pgs: 89-90

"In Lake St. Lucia, Natal, South Africa, there are
annual migrations of shoalfish out of and into the
lake from the Indian Ocean, either to spawn, or to
feed....

The annual movement of the mullet shoals is fairly
constant, and between mid-April and Mid-May each year,
large numbers of crocodiles move down from northern
and open stretches of the lake in response to the fish
shoaling; others move up from river systems to the
south.

They congregate in an area known as the Narrows, a
channel less than 500 meters (550 yards) in width....
Examples of cooperative feeding can be observed with
several crocodiles spreading out in a semicircular, or
line formation, which blocks the passage fo the fish.
Each crocodile maintains its place in the line and
snaps at approaching fish. There is no fighting over
prey, shifting position and leaving a gap in the ranks
would lessen the chances of successful prey capture."

Far more interesting, are the numerous cases of
cooperative feeding, seen in crocodiles. 

Another quick blurb (pg 90):

"Up to 30, or 40 crocodiles may arive at a buffalo
carcass, and there is a record of 120 sharing the
carcass of a hippopotamus in the Luangwa river,
Zambia.
Here, because of space limitations, not all the
crocodiles were able to feed at the same time. They
encircled the carcass, awaiting their turn, moved in
to procure a portion, then retreatd to the outer edge
of the circle to devour the morsel. Despite the
considerable movement to and from the carcass, there
was no evidence of fighting among the large group of
crocodiles.

...

[Regarding how crocs handle meals that are too small
to death roll, but too large to swallow whole]. In
such circumstances, a second crocodile bites the
carcass and holds it while the first reptile rotates,
or both may rotate in opposite directions. Each
crocodile, and there may be several, eats what it
tears off without any hostility to the others, then
waits it turn again."

I also recommend Nova's special on crocodiles (aptly
named: Crocodiles), which actually shows crocs
performing this last behaviour. IIRC it shows two
crocs bracing a large hippo carcass, while other crocs
came in to feed on it. It took all night for every
croc to get their fair share.

As for the intelligence mentions in this thread, I
would keep in mind that human beings have a tendency
to bias intelligence tests towards things that we,
ourselves, can do. As such, most of these tests are
very unfair. A recent survey of this, can be read in
the recent Science article on avian intelligence.

As for the pack hunting issue; to quote George
Harrison when he guest starred on The Simpsons: "Eh,
it's been done."

See: http://dml.cmnh.org/1998Mar/msg00561.html

for a thorough take on this matter (the thread for
this was huge).

Jason

=====
"I am impressed by the fact that we know less about many modern [reptile] types 
than we do of many fossil groups." - Alfred S. Romer


                
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