Re: natatory Geochelone

[Ronald Orenstein <ornstn@home.com>]

At 11:53 AM 02/07/2000 +0200, Juergen Peters wrote:
> > In the case of the Galapagos tortise, this makes sense to me. Being cold
> > blooded, these animals would not need to eat for a long period of time,
> > and could therefor endure long ocean voyages.
>
> But most probably they did not reach the Galapagos Islands by swimming,
> as someone mentioned here, but as juveniles on drift-wood etc.

Actually, according to tortoise experts I have talked to about this, there 
is every chance that they DID get there by swimming.  It seems that the 
tortoises on the Indian Ocean islands at least (and I suspect the Galapagos 
is a similar case) are not cases of insular gigantism but relicts of giant 
tortoise populations on the mainland; if juveniles were the colonizers you 
might expect some smaller tortoise species to be established there as well. 
I have been given eyewitness accounts, for example, of Aldabra Tortoises 
swimming out to sea; the adults are quite capable of this, and may well be 
able to withstand long fasts better than juveniles.

--
Ronald I. Orenstein                           Phone: (905) 820-7886
International Wildlife Coalition              Fax/Modem: (905) 569-0116
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Mississauga, Ontario, Canada L5L 3W2          mailto:ornstn@home.com