I’ve been wondering lately about the amount of time different animals spend in sleep. Is there a pattern or rule of thumb or is it all just a jumble of different adaptive strategies that vary wildly from one animal to the next ?

I’ve heard that predator species sleep more then prey species and that prey species often sleep/doze many times per day. But from my casual observations this doesn’t seem to be universal. For example, hawks and pigeons both seem to sleep the same amount of time-- from sun down to sun up.

Does complexity of the central nervous system have a correlation? The fish in my aquarium are active 24 hours per day, but I suppose they may be sleeping in micro sessions and may actually be sleeping a larger percentage of the day than I do?

What about brain size-to-body mass ratio? Cats seem to require more sleep than humans, but then maybe this is less a function of brain size-to-body mass ratio and more an indication that for most of our evolutionary past the ancestors to humans were a prey species? Then how do the sleep requirements of dolphins (a predator species) and chimpanzees (a mostly prey species?) compare to the time humans spend in sleep?

Perhaps there is a correlation between metabolic rate as measured by the number of breaths or heartbeats per minute and the time spent in sleep? These rates appear to affect brain wave activity in humans.

And this last question leads me to the claim by many spiritual and religious traditions that as an individual progresses in meditation and/or prayer he or she needs less and less sleep. From what I’ve read (and hopefully, without going off topic here) there appears to be some validity in this claim, especially in regards to those who seem to have more or less conscious control of their brain wave activity.

I have no expertise in any of this so please excuse the naiveté of some of the questions. Please feel free to correct any misconceptions or invalid assumptions. I would be very interested in your comments or library suggestions… for a layman .


t.



Edited 1 time(s). Last edit at 04/24/2005 10:03AM by teacup.