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Re: Hibernation and KT boundary?



On Richard Swigart's mail, and Betty Cunningham's reply

> Subject: Re: Hibernation and KT boundary?
> Date: 12 February 1998 23:49
> > Angela Chaves brings up a good question.  I have from time to time
taken up
> > Dr. Baaker's challenge, and thought about the animals that made it
through
> > the K-T event.
> > 

On factors influencing survival across the K-T:  I believe being able to
burrow was important.  Many if not most mammals could, and dinosaurs almost
never did - though Darren N. says something - I think it was a
hypsolophodont - did.  Hibernation itself may not have been an essential
factor.  Another important thing was being able to eat insects or detritus.
 Of course many mammals were herbivorous, but the survivors may have been
able to eat roots which are often designed to survive across intervals that
leaves could not.  Not being able to burrow AND relying on leaves or big
meat was a dangerous combination.   A strict rule of survival was not being
over a certain weight - I think that was 40lbs, though I may be wrong. 
Some kind of shock wave must have travelled through the earth after the
impact.  This will have had the effect similar to falling through some
distance if it was big enough.  Smaller animals would have survived this
better.

I suspect that not only non-polar birds crossed the K-T  (said Piglet).

I'm beginning to think that modern birds were not so badly affected by the
K-T event after all.  (This is contrary to Feduccia, so . . .) . . .and . .
... if we know so little about Cretaceous birds, imagine how much we don't
know about the Jurassic & Triassic!   Mind you I do think birds didn't
really get going properly until the end of the Jurassic, and I'm beginning
to convince myself of a reason for the delay.   The head start that
pterosaurs had was very difficult to overcome, but, instead of just going
extinct, early birds always had the ability to lurk on the edge of that
niche because they were just so damned good on the ground - in other words
they straddled the two niches (small ones did, anyway) until, very slowly,
feathered flight was perfected.   Until they had lost their claws and teeth
species could go back to mainly running with a bit of climbing, then become
more arboreal and practice their jumps, then go back again.  I have not
expressed this very scientifically, but it would be easy for some people to
believe that flying ability could have been lost then regained multiple
times until claws were lost.  Of course modern flightless birds are down
from the trees for good.  (I think this is probably straight from _PDW_.)

John V Jackson    jjackson@interalpha.co.uk

(Wannabeasaurus   beecee-effia - & proud of it!)