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Re: Theory of Non-Avian Dino Extinction



>Do you think that temperatures would have been cold enough to
>pressure dinosaurs to need to hibernate.  Without the pressure of a
>climate making those kinds of demands would nature select for
>hibernation behavior?


Hibernation may not be triggered by temperature changes. Decreasing photic
periods may be as important (if not more so) in triggering the onset of
hibernation. Consider it this way: Why do animals hybernate? Because,
during winter at higher latitudes, food resources are rarer and so by
slowing down the animal places less demands on its body for food. Why is
food more scarce in winter? Because the decreased photic period reduces
plant growth. With the current distribution of earths continents, winters
are relatively cold events but they were not so cold during the Mesozoic.
However, the decreased photic period of winter would have been comparable
in the Mesozoic to that of today. This means that food would have been more
scarce in high latitudes during winder in the Mesozoic. For dinosaurs
living at these latitudes, there are two options; hybernate or migrate. In
at lease one case (the Victorian Dinosaur Cove Site) it has been suggested
that the dinosaurs were too small to migrate in and out of the area.
Hybernation would be an option here.

While on things Mesozic Victorian, the scuttle-butt around the traps here
this week is that Tom Rich has found Australia's third Mesozoic mammal. I
gather that this one is not from Lightning Ridge and may be from Victoria.
I'll keep you all posted.

Cheers,

Paul


Dr Paul M.A. Willis
Consulting Vertebrate Palaeontologist
Quinkana Pty Ltd
pwillis@ozemail.com.au