>bill at nsma.arizona.edu (Bill Skaggs) writes:
>> >Yes, this is known as the "radiator hypothesis". It was presented in
> >a Behavioral and Brain Sciences article a little while back, together
> >with assorted critical review.
>> >As for my own opinion, it seems to me that Mother Nature could have
> >worked out a better way of cooling off the brain, something that
> >wouldn't turn animals into inert blobs and leave them at the mercy of
> >any predator that happens to wander along.
>> If you fell asleep at the water hole you probably wouldn't pass on your
> genes. If you hid and built a nest, maybe you would. I haven't heard many
> really appealing theories of sleep, but it seems to be metabolically
> efficient -- shutting down arousal/activity for hours a day can reduce
> energy demands, hence the number of hours necessarily spent
> foraging/hunting. Probably also reduce water demands. If this time was
> spent in a nest, hole, quietly perched on a twig, or standing up in the
> middle of a herd, it might also *reduce* predation risk, no?
>>>> I think that the predation stuff is only a small consecuense of
sleep. As brain become more and more complex, animals need to reduce brain
activity in order to recover some functions. Evolutionarily talking, this
could be more important than the fact that some individuals could be at
risk of predation. I'm not sure if sleeping could reduce predation risk; it
is important to decide on which kind of animals we are talking before
discuse if this evevnt could reduce or not predation rate.