[extropy-chat] big fierce animals

[Emlyn]

On 25/10/05, spike <spike66 at comcast.net> wrote:
> A while back I read _Why Big Fierce Animals Are Rare_ by Paul Colinvaux, an
> ecologist.
>
>
> I had a thought when I heard of this title.  If
> one thinks of carnivorous dinosaurs is tempting
> to imagine that bigger is always better: they
> can devour more kinds of beasts, run faster,
> etc.  But if one imagines scaling upward linearly,
> the strength of the muscles increases as the square
> of the linear dimension, whereas the moment of
> inertia of the body increases as the fifth
> power of the linear dimension.  Result: the
> bigger the dinosaur, the slower he can react.

You can get very small carnivores, probably for exactly this reason. I
guess you don't have to prey on everything, just critters around your
size range. I imagine another reason is that the bigger you are, the
more food you need, so every bit of bulk you put on (as a species)
must be justified by increased ability to feed. Hard to do!

It doesn't seem to be common knowledge that Australian marsupials come
in carnivorous varieties, mostly quite small (mouse size up to rabbit
size). Many of them are amazingly cute, and incredibly aggressive; I
remember seeing a wildlife show a while back where a fellow was
holding out a finger that had a little marsupial mouse hanging on to
it by its teeth. Shades of the chickenhawk in the warner bros
cartoons.

Here's a summary of carnivorous marsupials:
http://www.australianwildlife.com.au/features/marsupials3.htm

Here's are some cute pictures of rainforest predators:
http://www.wildlife-australia.com/bandicoo.htm

Scroll down for a good Quoll photo:
http://www.quollseekers.com/Fact%20Sheet%201.htm

Some of these guys aren't actually actually predators so much as
carrion eating scavengers, and I guess they sometimes use a
combination of strategies.

>
> An ecological niche for smaller carnivores
> becomes apparent.  They could be built with
> a relatively small but powerful jaw like a
> pit bull and a short but heavily muscled
> neck.  The relatively small carnivore could
> make its living by running past a large
> carnivore and ripping a hunk of flesh out
> of the big guy's leg, then running off with
> that one bite before the larger carnivore
> could react.  Do you suppose this is how
> velociraptor velocirapted?
>
> spike

A specialisation of chewing only on predators is probably a pretty
tough one to carry off. But as a partial strategy it probably
happened, especially to wounded large predators.

--
Emlyn

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