Do Hermit Crabs Sleep?

Hermit crabs make for low-maintenance, easy-care companions as pets, but some insight is vital to maintain and keep them healthy. Their sleeping patterns are one of them because they are nocturnal creatures meaning they like to sleep during the day and come out at night. This article will cover everything there is to know about a hermit crab’s sleeping patterns, going over the various factors that influence it. Read on to see what they are.

Do Hermit Crabs Sleep?

Yes, hermit crabs do indeed sleep, and they do so for about 6 to 8 hours a day. As nocturnal decapod crustaceans, they may seem a bit lazy to you during the day, but this is the time when they get all their rest. Nocturnal creatures primarily sleep during the day and are active at night.

Do Hermit Crabs Always Sleep During The Day?

Besides being nocturnal creatures (meaning they are active during the night), the other main factor that contributes to why hermit crabs sleep during the day is the sun.

Hermit crabs do not like to bask in the sun, and due to the fact that they have soft bodies protected by an exoskeleton, they are very susceptible to dehydration if conditions get too hot. They also use other animals’ discarded shells to further protect them from the sun to stay cool. 

Although hermit crabs are tropical creatures and require a sufficient amount of humidity in the air (approximately 70 to 80 percent) so they can breathe via their gills correctly, if it gets too humid, they will leave the comfort and safety of their shell and bury themselves in the sand until humidity conditions are more favorable. 

Do All Hermit Crabs Sleep During The Day?

A research study on four tropical intertidal hermit crabs from Southeastern Brazil indicated that different types of hermit crabs might rest and be active during various times of the day, depending on various factors and observations. 

The observations of these four species of hermit crabs were done at 2-hour intervals that took place over a 48-hour period (two days). 

Three various patterns of activity and rest could be distinguished by observing these crabs in this environment, and the results were interesting. 

Two out of the four species exhibited circadian rhythm patterns that suggested that their resting peaks were that of during the morning and afternoon, while activity for these species was primarily in the evening. 

If you don’t know, circadian rhythm is a naturally occurring internal process that many animals, organisms, and plants respond to. It is a process that regulates the sleep and wake cycle of these plants, animals, and organisms that have it and is governed by light and dark (day and night). 

The third species of hermit crab had a circadian rhythm with two inactivity peaks corresponding to dawn and evening. The researchers hypothesized that these hermit crab’s circadian rhythms could correlate to the semi-lunar tidal cycles that occurred in the area.   

The last species of hermit crabs were observed to have high activity periods throughout the study and were not susceptible to circadian rhythm (any form of day or night conditions).

Considering this research, it would suggest that depending on the species of hermit crab, different species could rest and be active during various times of the day. Thus, we can conclude and assume that not all hermit crabs will sleep during the day, but their sleeping behavior will rather depend on what species they are. 

Do All Hermit Crabs Sleep The Same Amount Of Time?

Although hermit crabs sleep between 6 and 8 hours a day, some factors could influence them to sleep for longer periods of time where they will remain in their shell or buried in the substrate (the material that sits at the bottom of an aquarium).

Some factors that could influence a hermit crab to sleep for longer periods or persuade them to stay hidden for longer can include;

  • Lack of humidity
  • Too much humidity 
  • Cold temperatures
  • Stress and anxiety
  • Evasion from other crabs and/or predators
  • Seeking privacy
  • Boredom due to lack of stimulation
  • Excessive light
  • Depression

How Do Hermit Crabs Sleep?

Hermit crabs are commonly found holding their shell over their eyes in addition to their legs sticking out of their shell when they sleep. In some instances, they have also been observed sleeping on their backs. 

However, no conclusive data has been drawn to determine the various characteristics of sleeping hermit crabs, and limited research and data are available on their sleeping patterns. 

Where Do Hermit Crabs Sleep?

Hermit crabs will typically sleep in their shells unless certain factors dictate that they should bury themselves in the sand. Although they prefer shade and climb trees to eat insects and vegetation, you will not find them scuttling under a tree, leaves, or in hollow stumps for shelter. 

Rather, you will find them closer to the water, taking shelter in or under rocks that are exposed by the low tide if they are not buried in the sand. Remember that although they do prefer more humid conditions, they still need to keep cool. 


We discovered that hermit crabs do indeed sleep and do so for approximately 6 to 8 hours a day. For the most part, we also found out that these 6 to 8 hours of shut-eye occur during the day because they are nocturnal. 

However, research indicated that various species of hermit crabs could have different sleeping patterns governed by differentiating circadian rhythms. 

If you are planning to get a hermit crab as a pet, then be sure to fill your terrarium with sufficient sand (substrate) because although hermit crabs do like to sleep in their shells, they will from time to time bury themselves in the san and sleep there.