Are Hermit Crabs Nocturnal or Diurnal?

Keeping a mini-colony of hermit crabs is pure fun. These little explorers are perhaps not very cuddly, but they do offer so much amusement to those who observe them doing “their own thing”.

From climbing plants and tiny branches to digging around the substrate, they can get extremely active once the initial shy phase is over. And sometimes, we even like to wait for night hours to watch them while being most active. So, are hermit crabs nocturnal or diurnal?

Hermit crabs are mostly nocturnal, meaning that they usually prefer feeding and exploring during the night. However, it is not uncommon to see them looking for new adventures during the days as well. Indeed, this is quite normal when they are held in captivity.

Hermit Crab Sleeping Habit

Hermit crabs are naturally designed to sleep during daytime. In the wild, when daily temperatures get really high, this is their only way of staying hydrated. Most of them hide in their shells while resting, to protect themselves both from heat and from predators.

However, their antennas are always alert while sleeping, so when anything or anyone approaches their shells, they will immediately wake up. It is commonly thought that these creatures require from 6 to 8 hours of sleep each day, but not continuously.

Some hermit crabs prefer resting for a couple of hours before heading to explore their enclosure and then returning to their sleeping session afterward. Just as people, they do not necessarily need to have equal sleeping habits, but rather feature an individual approach.

Furthermore, these animals are really sociable so it is not uncommon seeing them sleeping together sometimes. And by together, we mean literally one on top of the other. This can be particularly amazing in cases of larger colonies.

Once the sun begins to set and the temperature levels slowly decrease, these pets will start becoming more and more active. Coming out of their shells, they will usually first head to their water and food dishes. And next, a whole night of exploring adventures awaits.

Noise & Chirping

If you are a light sleeper, keeping your hermit crab enclosure in your bedroom is probably not the best idea. In fact, these pets can get pretty loud during nighttime. And not only because of climbing around the enclosure and turning things around.

Their bodies can emit some really interesting noises, too! So, if you hear your pets chirping or croaking, it probably means they are having a late-night chat (or discussion) between them.

It is believed that they are able of producing such sound by rubbing two parts of their bodies (more precisely, legs) inside the shell, known as stridulation. They usually chirp when feeling frightened or angry, more as a warning sign to those who touch them.

However, it seems they can also chirp when feeling good and simply wanting to communicate. If you own these pets for several years, they can even react to your voice by chirping.

Light Requirements

In order to thrive, hermit crabs need to have a natural cycle of 12 hours of daylight and 12 hours of darkness.

This is the best way to re-create their life in the wild and allow them to adapt their feeding and sleeping habits in accordance with that. Otherwise, you are risking having extremely stressed and unhappy pets.

Therefore, what is essential is to provide their enclosures with a bulb with daylight. This can double as a heating source as well, depending on the temperature parameters across your tank. However, they do not really need a night bulb.

Although some owners prefer setting an incandescent night bulb in their enclosures, this is more for allowing them to observe their pets when being most active, not for their pets. Such light options are not harmful to hermit crabs, but they are not helpful either.

Are LED Lights Safe for Hermit Crabs?

LED lights are not known to being harmful to hermit crabs. If you are using LED lights during daytime, this should be perfectly fine, as long as the temperature and humidity levels are ideal.

LED lights are pretty safe because they do not produce any heat, so many owners prefer them as an alternative to classic light types. However, if you are using a red or blue LED light in order to observe your pets during nighttime, it would be best to only keep it on for a couple of hours.

These cannot imitate dusk very well as tropical light bulbs can, so they could potentially confuse the cycle of your pets.

Do Hermit Crabs Prefer Light or Dark?

Being mostly nocturnal creatures, it is probably safe to conclude that hermit crabs feel more comfortable when it is dark. They usually never feed before dusk, and they also become extremely active when temperatures are slightly cooler than the daily ones.

However, keeping them in the dark at all times is certainly not good for their well-being. They do require to have a natural cycle of 12 daylight hours followed by 12 hours of darkness. This is essential.

Can Hermit Crabs See in the Dark?

Hermit crabs can see simply fine in the dark. Their compound eyes are designed in such a way to allow them to see (even if barely) in the darkest spots of their enclosures.

They do not see perfectly when there is absolutely no light around, but they rather manage to just walk around and be warned if something or someone approaches. Their antennas are greatly helpful for them to move around, too.

Wrapping Up

Although as categorized as nocturnal animals, it does not have to mean that your hermit pets will spend all day sleeping. Indeed, they prefer feeding and exploring around their tanks once dusk starts to approach, but they will happily entertain you during daytime as well.

Offering them 12 hours of daylight is essential, as this will greatly help them maintaining a healthy living schedule. An incandescent night bulb is not necessary, but it will not disturb them either, as long as it replicates well dusk hours.