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Re: Crocodile Survival Casts Doubt on Dinosaur Big Freeze



I don't think crocs are a good analogy for dinosaurs.
They are clearly different . For a start they are (and were) adapted to an
environment which resists rapid temperature changes (rivers/lakes/marine)
so would not be so badly affected by rapid day/night, summer/ winter
temperature changes compared with land dwelling forms.

Also crocs are not built for the fast life. They are physiologically
adapted for the easy life and in fact extended activity is often fatal. For
several years the Australian government had been removing large crocs (> 10
feet) from waterways close to human habitation (they were to be sent to
zoos or released futher away from humans). However, within a day ar two of
being caught, most had died. It was eventually discovered that all the
struggling that the croc puts up whilst being caught created a massive
oxygen debt as the croc goes into anaerobic respiration (as an example,
most organisms go into anaerobic respiration during strenuous exercise, for
instance running, because oxygen cannot be delivered to the tissues fast
enough. What happens is that glucose incompletely catabolized to produce
lactic acid. Afterward the lactic acid has to be oxidised and removed, the
amount of oxygen needed to do this is = the oxygen debt). The physiology of
the croc is not able to redress the balance afterward and the toxins are
not removed from the blood and they die. These days crocs are sedated
immediately and so survive to be released elsewhere.

So physiologically and ecologically the croc was in a good position to wait
out the initial fluctuations  and see.

Chris