22 Surprising Facts About Spider Sleep


Spiders couldn’t be more different than humans. They have way too many legs and eyes and are far too scary to be compared to even your worst playground bully. So, if spiders are so incredibly different from humans, do they sleep? And if they do, is sleep even important to them?

All spiders sleep but not in the same way as other animals. They cannot close their eyes, nor do they become unconscious of the world around them. A spider sleeps by lowering its metabolic rate and keeping its body very still. However, it can become entirely active again within only a few seconds.

This article delves into the 22 most interesting fact and frequently asked questions about spider sleep.

Orange and black spider sleeping inside hole in rock

1. Spiders Don’t Sleep Like Other Animals Do

If you think spiders have regular bedtimes and lay down to sleep like most other animals, you’d be mistaken. Spiders don’t lose consciousness when they sleep, like most animals and humans. Instead, they essentially power down their bodily functions and metabolism to preserve as much energy as possible between meals.

Spiders’ sleeping habits are honed for their survival. Instead of shutting down their senses and becoming oblivious to the world around them, they simply lower their energy output as much as possible, all while maintaining a solid sense of what is going on around them.

A ‘sleeping’ spider won’t be groggy if a predator or prey approaches but will spring into action immediately as if they weren’t just taking a lazy nap a second earlier.

2. Spiders Can’t Close Their Eyes

Spiders can’t close their eyes simply because they don’t have eyelids. Like most insects and arachnids, spiders have compound eyes. Compound eyes aren’t filled with liquid, nor do they rotate in their eye socket. Instead, they are made of multiple layers of cells that each provide a different angle and type of vision.

Spiders’ eyes don’t need eyelids to keep their eyeballs moist since they aren’t really eyeballs, nor do they contain any liquid. They also don’t need lids or lashes to protect against damage or dirt, as their eyes are covered by the exoskeleton, making them very durable.

Since spiders can’t close any of their up to eight eyes, it’s not all that surprising they can’t really sleep in the same way other animals do. And even when they’re napping, they are always aware of their surroundings.

3. Do Spiders Rest?

Despite their inability to sleep, spiders need to rest and spend much of their day doing so. When a spider isn’t busy burrowing, catching prey, or building a web, it will usually lower its metabolic rate and keep incredibly still. This reduces the amount of energy used by its body and is the spider version of resting or napping.

During this time, the spider is acutely aware of its surroundings since its brain doesn’t ‘shut off.’ If a threat or food source approaches, a spider can instantly resume its activity without the need to wake up and feel groggy for a couple of seconds like the rest of us.

4. What Does it Look Like When a Spider is Sleeping?

Typically a sleeping spider will stay very still for an extended period. This is because they are trying to conserve their energy by reducing their movements. Some spiders hide when they are sleeping, while others do not, and can take their nap in a range of weird positions, from hanging upside down to playing dead or tucking their legs in beneath them.

5. Spiders Can Yawn

There’s little to no research on why or how spiders yawn, but many of them do, particularly tarantulas.

Want to see a yawning tarantula in action? Then check out this video:

Whether they do it when they’re sleepy, after they’ve eaten, or just for no reason at all is unknown. Scientists don’t seem to be interested in the cause of spider yawning, which could mean it’s just an amusing behavior with very little scientific reckoning behind it.

Despite this, spider yawns are pretty cute, and does make it seem like their periods of rest should be counted as naps.

6. Spiders ‘Sleep’ in the Day

Most, not all, spiders are nocturnal creatures. This means they are most active at night when it is less likely they will be spotted by predators, especially birds.

They spend their nights doing some hunting of their own and usually retreat to their burrows or webs once a day breaks. For this reason, most of a spider’s rest will take place during the day, when they are hiding from potential threats or simply minding their own business.

7. Spiders Have a Circadian Rhythm Too

Like all humans and other animals, spiders have an internal biological clock or a circadian rhythm that regulates their experience as a full day. Circadian rhythms control an animal’s need for sleep, food, and hormone secretion.

So, despite spiders not really sleeping in the same way we do, their bodies are still guided by their biological clock. Humans, other animals, and even bacteria follow an average circadian cycle of 24 hours. All except for spiders, who have a unique rhythm that is much shorter than everyone else’s. [Source]

8. How Long Do Spiders Sleep For?

Because spiders sleep intermittently throughout the day and night, it’s not as easy to determine exactly how much sleep they get in one day.

Usually, spiders will sleep more if there’s not a lot of food available or if they’ve just done something that required a lot of energy, like making a web. If there’s nothing for them to eat, a spider may be forced to sleep to make sure it doesn’t starve before a suitable snack once more enters the area.

Overall, spiders can average around 8-12 hours of sleep a day, broken into intervals as short as a minute or two, to hours without interruption.

9. Do All Spiders Sleep?

Yes, all spiders need to sleep at some point during their day. It is essential for energy conservation and is what most spiders do when they’re not hunting, burrowing, or spinning their webs.

Different spiders also sleep at different times and for different amounts of time. Some sleep upside down, others standing up, and some even sleep with their legs tucked beneath their bodies, essentially playing dead.

10. Some Spiders Sleep Upside Down

Most spiders, like other animals, live their lives upright, spending their days with their legs supporting their tiny bodies against the forces of gravity. Some spiders, however, do exactly the opposite and spend their lives upside down.

These spiders hunt, eat and move, all while hanging upside down from their webs. These spiders typically have longer legs than others, which makes it way more difficult to walk normally. [Source]

These spiders also sleep upside down. They are either suspended by their webs or wrapped in a protective layer of the web as they nap, suspended high above the ground. They are the acrobats of the spider world.

11. Do Spiders Sleep on Their Backs?

Spiders don’t typically sleep on their backs. The only time when this may occur is during molting.

Molting is how a spider sheds its old exoskeleton to make way for a new, bigger one that can accommodate its growing body. During molting, a spider usually lies on its back to make the process of cracking its carapace and wriggling out of its old exoskeleton easier.

Some spiders may rest for a few minutes while molting, which could count as sleep. However, if your spider is lying on its back and is definitely not molting, something might be wrong.

If this behavior is exhibited along with curled-up legs, there’s a chance your spider may be dead and not sleeping or molting.

Large black spider hiding under side of rock

12. Spiders May Sleep, or Hibernate, Through the Coldest Winter Months

Many species of spiders hibernate during winter. Others most probably die once the cold weather arrives. Spiders are not suited for freezing temperatures, so those living in areas with cold winters had to adapt to survive.

Spiders usually hibernate in the early winter or late fall. They will hide away in burrows, cracks in walls, or under tree bark. Some spin webs to help protect them against the elements.

Once the cold sets in, spiders go into a sleep-like state, lowering their metabolism rate and putting an end to movement entirely. They also secrete a chemical that helps further protect them against freezing.

Hibernating spiders typically sleep throughout winter, and some can keep this up for almost six months before needing to leave their hiding place in search of food. [Source]

13. Do Spiders Tuck Their Legs in When They Sleep?

During hibernation and pseudo-sleep, spiders may tuck their legs beneath them to keep themselves warm and help lower their energy requirements even more.

This is especially common in hibernating spiders. However, this tucking in of legs is very different from them being curled up. A spider’s leg movements are controlled through the hydraulic pressure of hemolymph, or spider blood, running through them.

If a spider is lying with its legs completely curled up beneath it, there’s a good chance it may be dead as there is no more pressure to help it straighten them.

14. Spiders Can’t Dream

Many animals other than humans are capable of dreaming. We’ve all seen videos of dogs whining and running in their sleep as they drift into dreamland.

For spiders, however, there are no sleepy imaginings of buckets of flies being deposited on their webs.

Dreams only occur when the brain enters REM sleep. This usually only occurs several hours after an animal dozes off. Since spiders do not really sleep and never enter REM, they can’t dream.

They spend their naps drifting between sleep and wakefulness and will never have a movie play out in their head while they rest as we do.

15. Different Spiders Have Different Sleeping Patterns

Similar to how not all spiders can hibernate, not all spiders share the need for the same amount of sleep. Different species have different sleeping needs and follow different sleeping patterns.

Jumping spiders may be more active during the day and sleep more at night. Australian redback spiders can sleep for up to six months without getting any food, while to other species sleeping for so long is unimaginable.

Just as some humans are early birds and others are night owls, spiders have different sleeping needs and go to sleep at different times of the day.

16. Where Do Spiders Usually Sleep?

Spiders’ preferred sleeping areas vary as much as their sleep needs. Some will sleep upright on a wall or a ledge inside a house. Others will burrow in the ground or make use of another animal’s burrow to hide underground and nap there.

Even others may make cocoons for themselves out of their web and sleep safely inside, while others do so suspended precariously from their webs. Typically a spider will be able to sleep anywhere that provides relative safety and some access to passing prey.

17. Can a Spider Pass Out?

Believe it or not, spiders can pass out and become unconscious, although only under special circumstances. Scientists have noticed some female spiders may pass out while mating due to the effect of the male’s pheromones.

Other spiders can lose consciousness when exposed to chemicals or drugs, although they typically reawaken soon after the chemical is removed and the smell dissipates. [Source]

18. Can Spiders Become Tired?

Despite their weird sleeping habits that, to humans, don’t sound like sleeping at all, spiders do need their rest. If they are not allowed to sleep, they can become tired and sleep-deprived like the rest of us.

An experiment conducted on sleep-deprived jumping spiders found that spiders who were kept awake reacted aggressively and far less logically than those allowed to rest naturally.

Instead of waking and analyzing their environment before reacting to a possible prey or predator, the exhausted spiders would immediately attack each other as soon as they became aware of the others’ presence. [Source]

Just like humans, spiders become cranky when they can’t get enough sleep.

19. Some Spiders Don’t Have 24 Hour Days

Most of the animals in existence have a 24-hour circadian rhythm, based on sun cycles and our perception of day and night.

Many spiders also follow this pattern, although a few spider species surprised scientists as they exhibited much shorter circadian cycles. These spiders, mostly orb-weavers, have days that range between 17 and 19 hours long, which was almost unheard of before.

These spiders are completely independent of the earth’s rotation and live their lives according to their internal clock. Despite the uniqueness of this behavior, having such a short circadian rhythm presents these spiders with several more obstacles of survival to overcome than others. Exposure to light resets these spiders’ internal clocks, essentially eliminating any ‘jet lag’ they may have felt due to their whacky sleep patterns.

20. Do Lights Keep Spiders Awake?

Spiders aren’t attracted to light like insects are. The only reason you may see them near a light source is that they’re hunting the insects around them. Light usually resets a spider’s circadian rhythm and can keep most spiders awake if it is constantly shone on them.

However, if you just switch a light on in a room, it won’t do much to keep a spider awake as they spend most of their day sleeping anyway. For light to keep a spider awake, it needs to be very bright and focused directly on the spider.

21. Can Caffeine Give Spiders Energy As it Does for Humans?

This may seem like a weird question to ask but, surprisingly, there’s an experiment based on it.

NASA scientists had discovered spiders exposed to toxic chemicals spun deformed webs. Under the influence of caffeine, scientists didn’t notice any increased energy on the spider’s part but were surprised by the incredibly wonky, deformed webs these spiders created.

The spiders were unable to spin anything even close to a normal web and were way more confused as to what shape to spin when compared to spiders under far more potent drugs.

22. Do Spiders Play Dead?

Yes, they do! And a spider playing dead can often be mistaken for a sleeping one. The spiders most likely to play dead are house spiders. They curl up whenever they feel threatened, whether by humans or possible predators.

Other spiders play dead to protect themselves from their fellow spiders, especially the case in those spider couples where the female eats the male after mating. We’re looking at you, Wolf and Widow spiders.

Conclusion

Although spiders don’t sleep in the traditional sense, they definitely need to rest to function normally. Like humans, different spiders follow different sleeping patterns and understanding this has helped us significantly deepen our knowledge of a spider’s life cycle and feeding, hunting, and web-spinning habits.

Brigitte Cave

Bridgitte grew up on a farm and eventually spent 5 years on Mahe Island in the Seychelles during her teen years. Her time living on a farm was spent mostly around animals including dogs, cats, cows, horses, and all sorts of fowl (chickens, ducks, and geese included). You can find out more about Bridgitte at https://mercurypets.com/our-writers/ Bridgitte is a keen horse rider and has competed in many showjumping competitions. She loves writing about pretty much all animals, and particularly dogs, cats, small mammals, horses and reptiles.

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