This is in my world of balloons and zeppelins, war and peace, day and night. Sleeping may be the least important thing but it is still important. On this world, the day and night cycle is 8.89 of their years and 21 of our years. So I ask, how would sentient creatures in my world sleep? Below are some features I need in it.

  1. They do need to sleep somehow so no alternative recharging
  2. They cannot enter the night
  3. They are sapient but do not use technology as the primary source of sleep (like space marines in war hammer 40k)
  • 4
    $\begingroup$ Could you link more about your world? From this question, I don't know any reason to treat sleep as different than it is in our world. I'm assuming you have a good explanation on one of your other questions, but you'd be able to get more answers if you didn't depend on SE-goers to visit all your questions in order. $\endgroup$
    – Cort Ammon
    Jul 17, 2015 at 22:06
  • 1
    $\begingroup$ Are you trying to create a world that has creatures which evolved on Earth, but not live on this long day planet? You might consider trying a less Earth-centric approach to the plant and animal life. Let the creatures evolve on your planet instead of trying to fit our creatures somewhere they don't belong. $\endgroup$
    – Samuel
    Jul 17, 2015 at 23:41
  • $\begingroup$ How exactly is a "year" defined if a day is longer? What does #2 mean? Same goes for #3. @Samuel has a lot of valid points... You'll also have a LOT of seasonal depression (far worse than Alaska). You'll have some massive temperature fluctuations over the years too. I'm not sure this planet would be particularly habitable by humans without a climate-controlled biosphere which artificially created a 25-hour day/night cycle. $\endgroup$
    – iAdjunct
    Jul 20, 2015 at 3:09
  • $\begingroup$ Flight is difficult on a planet with 21 year days. You will get som ridiculously powerfull winds. $\endgroup$
    – Taemyr
    Jul 20, 2015 at 9:17
  • $\begingroup$ You know that the North and South poles share one interesting characteristic, when it's day in one, it's night in the other. The thing is, each night/day cycle lasts aproximatly 6 months. Your question has essentially the poles' lifestyle has an awnser $\endgroup$
    – Oak
    Jul 20, 2015 at 13:37

2 Answers 2


Having evolved on the planet, one option would be they sleep like dolphins, half their brain at a time. They might even have different personalities, depending on if one half or the other or neither is sleeping. This could allow some very 'alien' outlooks for the story. Maybe full unconsciousness really only happens with injury or sickness.

Another possibility is just taking naps. many species nap often. More than likely a nap time would be a bit staggered so someone is always conscious or aware of the surroundings to protect against attacks, either enemies or predators. I would expect in any group of people that some percentage is always sleeping, even during a party. It might even make them feel secure to nap.


It might give you insight to look up Circadian rhythms. Much of the sleep cycle is regulated by light and dark cycles. I recall reading an article where they did an experiment with humans with no changes in light cycle and no access to clocks and they settled into a 18 hour sleep wake pattern.

This might make what bowlturner said be the way to go. Think about how creatures would evolve with that light/dark cycle you mention above. Also note in the wikipedia article they mention that some reindeer above the arctic circle only experience circadian rhythms when the dark/light cycle is around, and none when they are in long seasons of dark. they would still need sleep but no longer are affected by the cycle.

Also look at some of the benefits of sleep. In some teaching and training circles it is suggested it allows for diffuse learning to take place (thoughts assimilated in patterns etc) and also for toxins to be flushed from the mind. Is there some other way that this can be accomplished through advanced technology? In which case sleep might just be something people indulge in for sensual pleasure (controlling their own dreams etc)


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .