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Re: Climate change
>Don't forget that a climate change would be much more likely to affect small,
>delicate animals than the big ones, like dinosaurs. If the global temperature
>drops 20 degrees, for example, who would survive, a 30-ton brachiosaurid or a
>6-ounce salamander? The brachiosaurid can pick up and move hundreds of miles to
>the south (or north) to get to a warmer environment, but the little salamander
>has to stay there and freeze. As Bakker once said, "It's cheap to be big."
I am not sure I buy this. There are actually distinct advantages to being
small in such situations. Your salamander can hide under a log, burrow into
a pond bottom or make another microhabitat shift to avoid weather extremes.
A larger creature has no option but to sit it out or move - and migration is
an energetically costly and risky process. Further, a large animal with
broad home range requirements may both find it harder to satisfy its needs
in an area after climate change than a smaller creature that can react to
environmental patchiness, and harder to move into another area without
running into competition from the critters already there.
Of course migration is an option several large mammals have used (eg whales,
elephants, wildebeest), and there are advantages to large size too - but a
conclusion that in general climate change will knock out the small things
and leave the big ones is, I think, not accurate.
>With the information that I have now, my vote is for a global dino plague.
Except that such a plague would also have had to affect pterosaurs,
enantiornithine birds, ammonites, many plant taxa, many foraminifer genera etc.
We may never know for sure, but I certainly would be skeptical of any
explanation for dinosaur extinction that was restricted in its application
to dinosaurs only.
Ronald I. Orenstein Phone: (905) 820-7886 (home)
International Wildlife Coalition Fax/Modem: (905) 569-0116 (home)
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