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Re: [Re: [CNN customn news: extinct lightweight racing tortoises]]

owner-dinosaur@usc.edu wrote:


> On 11 Oct 1998 archosaur@usa.net wrote:


> > That was interesting, although they forgot to mention that large tortoises

> > like the Galapagos tortoise actually have honeycombed their shells, which

> > drastically reduces the weight.


> Presumably this honeycombing would continue to protect against large

> predators.  This is evidence that the real penalty against large tortoise

> size is predation at the nest, i.e., a large tortoise provides amplified

> cues to would be predators.  Otherwise we would have giant tortoises on

> the mainlands, wouldn't we?


The honeycombed shells aren't as strong as the normal tortoise shells, but
they are still strong enough to hold off an attack.

As for why we don't have large tortoises on the mainland anymore, I"m not
sure. The pleistocene had _Colossochelys atlas_ roaming through Asia. And up
to near present day we had the strange, horned, meiolaniid tortoises living in
South America, then Antarctica, and finally Australia. So it's not like they
were strangers to mammalian competition.

Archosaur J

P.S. Sorry if the list gets this twice, but netaddress is acting up on me


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