Unless you’re an avid arachnid lover, or own a spider yourself, I bet you’ve never considered the question “do spiders sleep?”.
It probably hasn’t even crossed your mind. And, if it did, you quickly eliminated it. But it’s a valid question. Spiders have been noted to have periods of non-movement. It may appear as if they are sleeping. You may have noticed spiders in a state of rest, but are they really asleep?
Spiders really do sleep. But spiders sleep very differently from humans. The spider has no eyelids and it cannot close its eyes. Spiders do have a method to decrease their metabolism and conserve energy which may seem like “sleeping”.
Like us, most animals sleep. Turtles, lizards, lions, even bears sleep. In fact, most animals close their eyes, lay down, and take a nap at times, sometimes for a full 8 hours like humans do. Some will sleep less and some will sleep more.
Spiders, however, don’t have eyelids, so closing their eyes is an impossibility. There’s no significant research about this topic either. So, what about the spider? Do you think it sleeps? Read on to find out.
Do Spiders Sleep?
Most spiders have a circadian rhythm, an active and inactive cycle, like humans. Some types of spiders are more active during the day (referred to as “diurnal”) while other species of spiders are active at night (or “nocturnal”).
Spiders do have periods of inactivity. These periods can be lengthy at times. Some tarantulas are known to be inactive for months. Spiders have very little variation in terms of their activity. Mating and eating are their primary areas of focus.
For spiders, each day is exactly like the last. Some spiders build webs to catch their prey while others build burrows and wait for prey to come by so they can make a snack out of them. However, while they are waiting to eat or mate, spiders can go into a conservative sleep-like state.
Spiders who build webs use an extreme amount of energy to complete it. So, you will see the spider rest for a significant amount of time. They can lower their metabolism to conserve energy. But spiders don’t lay down and sleep like humans do.
Conservation of Energy
While spiders don’t sleep like humans or other species of animals, spiders will tuck their legs underneath them and slow down their metabolism. This allows spiders to conserve energy. If waiting for prey, spiders will conserve energy until the prey is available.
So, if there are long periods of time when prey is not available, a spider will go into a state of lower metabolism, or “sleep”. This will conserve energy until it’s needed. But, what if the prey comes by while a spider is in this lower state of metabolism?
Most animals, when they sleep, have REM sleep. REM sleep, otherwise known as “Rapid Eye Movement” sleep, is when animals are deeply sleeping. During this time, animals are having rapid eye movements. This is known as a dream state. But, spiders don’t ever enter REM sleep.
Do Spiders Dream?
Without REM sleep, spiders don’t get into a deep sleep. Spiders do not dream as most animals do. To decrease the stress of daily living, spiders will lower their metabolism and rest. This allows the spider to avoid issues related to long periods without “sleep”.
This keeps spiders alert, and they are able to cognitively sense the world around them. Spiders rely on many other senses as some spiders only distinguish light and dark. They perceive vibrations, and even temperature changes will alert them about their environment.
But most animals will go into a state of REM sleep. Lions, for example, will go into REM sleep and will not be aware of an antelope passing by. Spiders are always in a state of semi-awareness because they don’t enter REM sleep. This is why spiders never miss an opportunity to catch their prey and easily escape their predators.
If their prey wanders by their burrow or gets tangled in the web, a spider will exit out of this conservation state and will feed whenever this happens. This allows them to be ever vigilant about prey and predators.
Have you ever been awakened from a sound sleep? I’m sure you have experienced this at some point in your life. You jump up wide awake with your heart pumping in your chest. You are disoriented and confused at first but, slowly, you start to get your bearings. Only then do you begin to realize what is going on around you.
This happens with spiders too. Spiders, because they are in a semi-awake state, “jump” awake whenever their prey or a predator is nearby. Sometimes, it does take significant stimulation to “wake” the spider up.
However, if startled, they will often move around in a protective mode. Once they have an opportunity to realize what’s going on, they will settle down and address whatever issue is at hand.
Sleep vs. Hibernation
Because spiders stay in a semi-aware state, it isn’t considered hibernation. But spiders may stay in a state of conservation with a lower metabolism which can last multiple days, and sometimes for even months on end.
Some spiders even have been known to create a resting place, which they build with dirt that is then used to rest on. Other spiders who build webs can enter this lower metabolic state or sleep-like state even while hanging upside down on their web.
Spiders may find prey to be limited at times and spiders will go into this sleep-like state. And this can be for an extended period. That’s why many people think spiders experience hibernation. But hibernation requires a state, just like sleep, during which the animal is unaware of its surroundings.
An example of this phenomenon is the polar bear, who can give birth to its cubs during hibernation and not even be aware it’s happening. It also occurs when spiders are in a growing phase. When spiders are in a growing phase, called molting, they will shed their skin, wake up and appear larger. And this process can take several months.
Other Causes of “Sleep”
To use the polar bear example again, polar bears hibernate during cold weather. If spiders get cold, they will also enter their lower metabolic state to conserve energy.
They pull their legs underneath them to conserve heat. But because they remain conscious, they are not considered to be hibernating. And, this happens with all species of spiders.
Perhaps you have noticed more spiders in your household during the winter months. This is probably due to the fact that spiders do not like the cold. During the colder months of the year, you will find them trying to get indoors or hidden in any nook or cranny they can find in order to stay warm.
In conclusion, no one can truly answer the question “do spiders sleep?”. However, we do know that arachnids don’t sleep like humans do. They can’t close their eyes because they don’t have eyelids. With that said, spiders do have a method to decrease their metabolism and conserve energy which may seem like “sleeping”.
This period can be short or long depending on the weather and a variety of other factors. Even insufficient prey can cause this state of lower metabolism. Spiders don’t like the cold and will enter this semi-awake state to conserve energy and heat.
Spiders don’t have periods of REM sleep. They don’t dream. They stay in a semi-awake state until the prey is available or a predator is near. Spiders who build webs often rebuild their webs every night and require rest after such an extraneous task.
As there is little research about this question, it is difficult to really know if spiders sleep. Most evidence indicates spiders don’t sleep, but they rest and often relax while lowering their metabolism and conserving energy.