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Crocodiles|Outlasting the Dinosaurs
I just received an Earthwatch press release (citing an interview posted on
the Nova web site), which notes that crocodiles can survive for long
periods without eating, and suggests that might explain how they survived
the KT extinction while the dinosaurs did not. I include the most relevant
part below; you can check the whole interview at the Nova site.
>This interview with a former PI (and former Earthwatch staffer) Perran Ross on
>the NOVA site might be of interest. Also interviews crocodile PI Alison
>Leslie on Nile crocs in South Africa..
> Outlasting the Dinosaurs
> An Interview with Dr. James Perran Ross
> NOVA: And crocs can go for long periods without eating, right?
> Ross: Yes, they have an awesome capacity to deal with starvation. There
>are numerous examples of animals not feeding for an entire year. They
>become desperately thin, but they're still active and are perfectly
>capable of feeding when food appears. So again, if the demise of the
>dinosaurs was caused by an asteroid-winter type of scenario, then
>crocodiles may well have been able to survive that.
> There is another element. Crocodiles, for all their ability to get their
>body temperature up when they have sunlight, do very well at low body
>temperature in the darkness. All their systems continue to work adequately
>well. There is some speculation that at least all the big dinosaurs were
>probably homoiothermic, or warm-blooded. That is, they had developed the
>circulatory and metabolic changes that enable one to maintain a body
>temperature independently of the surrounding temperature.
> If this was so, they constantly had to pay the great cost of becoming
>warm-blooded, which as we know ourselves is you have to eat all the time.
>The energetic cost of maintaining your body temperature burns up more than
>80 percent of what you eat. So dinosaurs that had made the commitment to
>becoming warm-blooded had given up their capacity to not eat for long
>periods. At the time that was a very effective trade-off, but when crunch
>time came with the asteroid or whatever it was, it was the crocodiles that
>still retained the primitive ability to continue to function at low body
>temperature and therefore not require as much to eat.