Thursday, November 10, 2005

mindCandy: Animal Sleep

Having spent some recent nights in downtown Manhattan, I got to thinking about sleep and how important it is for my, and other humans', sanity (I'm also thinking of starting the Coalition Against Noise Pollution, but I'll save that for another time - all praise the mighty earplug!). :-)

All mammals and birds sleep, but we're not sure whether all reptiles, insects, fish, and other creatures do. Generally, carnivores tend to sleep longer than herbivores. The rationale being that, after a large carnivore like a lion eats their freshly killed meal for the day, they have little reason to waste their newfound energy wandering around aimlessly - so they sleep. In the case of a lion, they sleep about 13.5 hours every day (a tiger is 15.8)! A giraffe, however, sleeps only 1.9 hours each day - partly because they must constantly "hunt" down their vegetarian fare and eat large quantities of it (unlike meat) to satiate themselves.

Now, chimpanzees, who have about 95% similar DNA to humans and are our closest "animal" relatives, sleep 9.7 hours a day. So why do we sleep only 8 on average? We should be more adept at getting our food (both vegetative and meaty) and so you'd think we'd sleep MORE than chimps. Well, I guess the concept doesn't apply without also considering a host of other details about the species in question (I expect that the fact that we have to go to work for 9pm and yet they tend to put the good shows on TV so late has something to do with it nowadays ;-) ). BTW, a human infant sleeps about twice as much as a human adult each day, but I suspect they're doing a lot of cranial and physical development in that time - not sure how the other animals' progeny works into these number, but it'd be interesting to find out (probably has to do with growth rate, etc.). An elderly human might sleep only 5.5 hours on average.

Man's best friend, the dog, sleeps 10.6 hours per day, proving conclusively that dogs aren't as lazy as those slovenly cats, who sleep 12.1 hours per day. A platypus sleeps roughly 14 hours a day, much of it probably spent in deep reflection upon its uniqueness in the world :-) , whereas pythons thankfully sleep for 3/4 of each day and I'd be into finding out how to make that closer to 4/4 for my peace of mind :-) . Sleeping a whopping 83% of their lives, the brown bat comes in at the top of the list for most rested with just short of 20 hours sleep each day (actually, second in the list, because my old roommate Nick was not included in this calculation ;-) ). Oh, and generally, large animals tend to sleep LESS than small animals (there's another dimension for ya) and, just 'cause it's cool - dolphins can sleep when they're moving.

I myself insist on a full 8 hours and basically sleep from 8 hours after I go to bed (or, more precisely, since I'm not the best sleeper - after I go to sleep), whenever that is on a given night. This has lead, constructively I think, to my never having pulled an all-nighter during university, believing and experiencing that a rested brain can create better answers than an exhausted brain can remember.

PS: Sorry for not posting yesterday - my exhausted brain forgot ;-) .
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11/10/2005 11:19:00 p.m.  


Anonymous Elisa said...

Great post!

I had no idea about pythons and their sleep habits but no wonder they're so hungry when they wake up ;)

I'm like you, I totally need (or think I need) 8 hours of sleep to feel completely refreshed and yet do I ever get 8 hours of sleep? No. No I don't and that's mostly my own fault. But when I do sleep nothing can wake me so I've never had problems sleeping, it's the GOING to sleep that is problematic for me.

There's also something to be said about using a computer right before you go to sleep. Apparently some say that you shouldn't use a computer for at least an hour before you go to sleep. I have no idea whether this actually works because I refuse to try it :P but some say it helps.

I totally believe that a well rested person is more alert, can be a better problem solver and work more productively than someone who's pulling an allnighter and is basically awake because of the 300 cups of coffee they've drank. That's why I try and get at least some sleep when a deadline is pressing on me because usually I end up doing my best work when I've cleared my head and start fresh.

There's also some scientific studies that suggest that we don't actually need 8 hours of sleep, so as long as the time we do sleep is uninterrupted and we maintain full REM sleep mode. Quality beat quantity and all that.

November 11, 2005 6:18 a.m.  
Anonymous Mark said...

The function of sleep may be to allow the brain to slow down and recover after a hard day of making and strengthening synaptic connections (the molecular basis of memory). This could explain why lazy infants sleep more than adults as they're in the process of hardwiring their brains from scratch. But it doesn't explain why the lazy chinchilla is sleeping 12.5h/day!

November 11, 2005 9:58 a.m.  
Blogger Jeff MacArthur said...

Wow, Elisa, I don't think I ever have a night where I don't use my computer right before I go to sleep (often to post these very entries :-) ), but I can see how it might hinder sleep somewhat.

And thanks for the interesting addition, Mark, I think that makes some sense too. All of this stuff (like everything in biology) is so dreadfully complicated and intertwined that it's hard to isolate the variables, but it is certainly interesting to examine nonetheless.

PS: I have never been a coffee drinker, so I guess that may have further prioritized sleep for me ;-) .

November 14, 2005 11:25 a.m.  
Blogger Ashok Kumar said...

Your study was about animals sleeping is very good. By visiting your blog I got valuable information.I want to say the importance of sleep.Sleep makes the mind and body fresh. The beginning for all the problems in the body is lack of sleep. If a person does not have proper sleep, then there is some problem with his mind or body. Sleep apnea is basically a condition that affects most people causing them to stop breathing for around 10-20 seconds as they sleep. The sleep apnea cannot be identified by the same person since it occurs during sleep. So if someone complaints about you for snoring, inform your partner or your family member who sleeps along with you to notice your sleeping condition during sleep. If you had sleep apnea, there are lots of medical procedures and devices to cure sleep apnea in a natural way.

June 17, 2010 3:37 a.m.  

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