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Re: Predator relationships

Michael wrote:
> > From:          Chris Campbell <sankarah@ou.edu>
>  Tim Caro's work indicates the cheetahs of the Serengeti average
> > about 40 kg and cheetahs of East Africa average around 60 kg.  Are you
> > indicating the differences in leopards are more distinct than this?
> Male leopards do have a greater disparity in size.  I think of it as
> cheetah can only be so large to do what they do successfully.  This
> would tend to keep both female and male weights down if the theory is
> correct.  

But what about _Acinonyx_pardinensis_, as well as
_Miracinonyx_inexpectatus_ and _M._trumani_?  _A._pardinensus_ was
unquestionable a cheetah, but was half again as large as the modern
cheetah; estimates are that it could run as fast or faster than the
modern form.  The same holds with the _Miracinonyx_ species.  Prey
species would be abundant in Africa, but competition with lions and
hyenas might be a much stronger mitigating factor; it's hard for those
guys to grab tommys, after all, so that may be the only prey animal the
cheetah can get away with grabbing on a regular basis.

> Leopards operate differently.  I don't know why male
> leopards are so much larger unless it is male-male competition and
> testosterone.  I'll have to find out. >

Sexual dimorphism seems to be the norm among cats; male lions are easily
twice as large as females, and then we have leopards and so on. 
Cheetahs are the aberration, as usual.
> ; I've heard that
> > cheetahs are successful in bringing down some 90% of the animals they
> > set out to catch (though Caro's work brings that percentage down to
> > about 25-50%, which makes me wonder where the first figure came from),
> > but they have a good half or more of their kills stolen so their success
> > rate dramatically (with Caro's work that would drop the success rate to
> > around 10-25%, which has gotta make you wonder how these buggers have
> > managed to hang on for 10,000 years).
> The figures I remember are 40% for leopard/lion and 70% for
> dog/cheetah.  But you're right.  Cheetah lose a lot of kills
> which does bring the number down.

The percentages I got are rough, and based on Caro's original work. 
These are averages for all prey types, and the numbers he gave were for
females of all types (no males that I could find, dunno why).  The
greatest success rate was, of all things . . . hares.  They bat close to
1.000 when it comes to hares for some reason.

> > All this talk about success rates brings me to something a bit more on
> > topic: what were the success rates of therapod hunters?
> I don't know.  Maybe the experts have some ideas.  I would like to
> hear their speculation, too.  I really was intrigued by the dino
> climbing the tree with prey.  Wish I had thought of it, even if it's
> preposterously improbable.

Climbing a tree wouldn't help dromies much; the Tyrannosaurs are just
too tall to make the strategy terribly effective.  It works for leopards
because hyenas can't climb trees and lions generally don't (they can,
but they don't tend to, really; I think they're just not terribly
comfortable up there, being so big and all).  Still, it's a neat idea.