Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ncar!ames!sgi!thant@horus.SGI.COM
From: thant@horus.SGI.COM (Thant Tessman)
Newsgroups: sci.bio
Subject: Re: novel: TWISTOR by John Cramer
Summary: structural integrity of six legged creatures
Message-ID: <32069@sgi.SGI.COM>
Date: 4 May 89 20:59:23 GMT
References: <100780003@hpcvlx.HP.COM> <980@gtx.com>
Sender: daemon@sgi.SGI.COM
Organization: Silicon Graphics, Inc., Mountain View, CA
Lines: 16

In article <980@gtx.com>, al@gtx.com (Alan Filipski) writes:
> In article <100780003@hpcvlx.HP.COM> everett@hpcvlx.HP.COM (Everett Kaser) writes:
>>The concept of six legged animals(especially mammal-like animals) has a long
>>tradition in fantasy and science fiction, and there are many examples of
>>creatures in our world with more than four appendages.  Most of them are
>>insects, spiders, and crustaceans.After reading this book, I got to thinking
>>about WHY there are no large six-"legged" animals on earth.  I came up with

[two possible reasons deleted]

The larger a creature is, the more structural sense it make to put the 
load-bearing members under the weight instead of out to each side.  I think
four legs is about all you can put under an animal without them getting in the
way of each other.

thant@sgi.com