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Re: Predator relationships



Jonathon Woolf wrote:

[snip]

> Modern cheetahs face two major problems: their extreme specializations
> for speed, and the fact that they live in an extremely predator-heavy
> ecosystem.  

Don't forget the fact that they're extremely inbred, and thus highly
susceptible to diseases and such.

> Their timidity is a survival trait.  A cheetah is kept fed
> by its feet.  Even a minor injury can be deadly for a lone-hunting
> animal that depends on speed.  Cheetahs are so reluctant to fight for
> any reason that a female cheetah will abandon her cubs rather than fight
> for them, something that as far as I know is unique among carnivores,
> and uncommon in mammals of all groups.
 
> That said, I find myself questioning the entire logic of using the
> Serengeti as a model for dinosaur interactions.  The Serengeti is unique
> among modern ecosystems in that it has _five_ carnivores of roughly
> equivalent size and predatory skill that go after many of the same prey
> animals: cheetah, lion, leopard, spotted hyena, and African wild dog.
> In other parts of the world, either there's one top predator, or the
> predators divvy up the available prey base either by habitat or by prey
> species.  But lion, leopard, hyena, and wild dog all chase pretty much
> the same prey species, and cheetahs occasionally will hit calves of
> wildebeest, impala, or other antelope as well as their favored Tommy
> gazelles.  Would any dinosaurian ecosystem likely have such an odd
> confluence of competing predators?

Sure.  Look at North America in the last 5 million years or so.  You had
American lions, cheetahs, mountain lions, dire wolves, sabretooths, and
a variety of smaller predators such as coyotes, bobcats, and the like. 
The Serengeti is an old system, and it typical of another time.  North
America and Europe were once much like it.  It's just a relic in modern
times, though quite a splendid one!

That said, I question using it as a model for the same reason I'd
question using it as a model for North America today: it's a whole
'nother ball game.  The Cretaceous had predators of drastically
different sizes running around, and the interactions had to be utterly
alien to our range of experience.  We simply have nothing to compare
them to.  

Chris