[extropy-chat] big fierce animals

The Avantguardian avantguardian2020 at yahoo.com
Tue Oct 25 04:41:04 UTC 2005

--- 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.

There is an element of truth to what you are saying,
Spike. But you also have to give adaptation its due.
There were and are numerous instances of gigantic
predators in the world. Tyrannosaurus rex with its
hollow bones, warm blood, and bird-style lungs (birds
have the most efficient lungs in the animal kindom)
was no joke. It was an amazingly successful predator
that survived to the very end of the age of the
dinosaurs. It was not outcompeted by anything more
fierce, it just couldn't handle an asteroid impact. 

Modern examples of gigantic predators that seem to
have no problem catching prey are kodiak bears
(largest on land), sperm whale (largest period),
saltwater crocodiles (largest reptilian predator),
great white sharks, and colossal squid (biggest
invertabrate predator). The cold-blooded ones can go
for long periods of time between meals and the
warm-blooded ones have adaptations that make them well
suited to their prey. 

A kodiak may be big and bulky, but you won't catch
even a whole pack of wolves brave enough to try to
take a bite out of one. One swipe of claws adapted to
break the bones of a bull moose would pulverize a wolf
and no wolf would take that chance. Plus they are
deceptively agile as anyone who has tried to catch a
salmon with their bare hands would tell you. 

> 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?

I don't think the velociraptors that were not starving
would employ such a tactic against an adult. Just like
hyenas don't eat lions and wolves don't eat bears.
It's just way too high risk to give those that
employed it many offspring. While T rex might have
been bulkier and less manueverable, it also had a much
larger stride. Young T rexes were probably fair game.
Although killer whale pods will prey on sperm whales
from time to time so maybe their was an occasional
take down of an old or wounded T rex by velociraptor
but it surely was not a staple food item. Please do
give the king of the tyrant lizards its due. 

The Avantguardian 
Stuart LaForge
alt email: stuart"AT"ucla.edu

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