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Re: Why Did Mammals Survive the 'K/T Extinction'?

On Feb 3, 2010, at 9:24 AM, John Bois wrote:
...this assumes that few or no dinosaurs burrowed, and that all surviving
mammals did. It also assumes that all surviving birds burrowed or were
cavity nesters. Below are two web sites reporting probable dino burrows in Montana and Australia. A good question is: some dinosaurs were living in and had adapted to extreme environments (the arctic, for example). Why didn't
they survive?

I agree; that is good question. As a potential, partial answer: the scenario you provided is only asserted if one supposes the conditions were so extreme as to be deterministic. That is, a "burrow or death" scenario (Izzard's "cake or death" routine comes to mind...) On the other hand, if we presume that the effects were more probabilistic in manner, then we might derive a better match to the observed patterns. If burrowing in dinosaurs was rare, and resources after the impact were highly limited, then being a dinosaur might make your chances of survival very low - they aren't zero, because you might be in the right place at the right time, but the likelihood is very low - meaning that only a small number are lucky. By contrast, if burrowing was common in mammals, and small size was also common (latter is pretty well known), then the amount of survival left to "luck" is lower.



Michael Habib
Assistant Professor of Biology
Chatham University
Woodland Road, Pittsburgh PA  15232
Buhl Hall, Room 226A
(443) 280-0181