Re: [Re: polar sauropods]

[archosaur@usa.net]

 JJ wrote:

> Elephants migrate - some of them do, a bit, but I don't see sauropods doing
more than say a 600 mile round trip in a season, and that kind of distance
wouldn't make an enormous difference.  300 miles north-south is say the
distance from London to northern England - only a slight climate change.>

> Perhaps if they spent the vast majority of their time on the march they
> could make a bigger round trip - say if they spent 300 days of the year
> But then if turtles could manage it...   or were those turtles marine?

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Does it really matter?

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> After all, someone mentioned plesiosaurs were found in those latitudes too.
But surely even marine turtles couldn't have survived in real cold.  I know
some amphibians can survive in astonishingly cold climates, but I think we may
be justified in taking turtles as some kind of guideline - does anyone know
how far north turtles live today?  Were the turtle remains as common as the
sauropods, or could they have been making a brief foray in a time of unusual
warmth?> 

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Turtles are the most climatically flexible (possible neologism here?) of all
of todays reptiles with the marine turtles _Caretta caretta_ and _Dermochelys
coriacea_ holding the record for coldest temperatures.

_Caretta caretta_ lives up in the temperate waters of the atlantic as far up
as Maine and _Dermochelys coriacea_ makes frequent trips to the arctic ocean
in search of jellyfish.

_D.coriacea_ withstands the cold by having lots of fatty layers surounding
it's body. In a word, it has blubber. It's actually quite interesting to take
a look at the anatomical makeup of a leatherback. They may be turtles, but
their built like whales.

If one goes back a couple million years then one can find the terrestrial
testudines, the Meiolaniids, living in the Antarctic.

Turtles just don't make for good temperature indicators.

Archosaur J




Jurassosaurus's Reptipage: A page devoted to the study of the reptilia

http://members.tripod.com/~jurassosauridae/index.html

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