Hermit Crab Behavior

Hermit Crab Behavior: Nocturnal or Diurnal?

Hermit crabs are nocturnal. They love darkness and they are mostly active at night. However, some hermit crabs are also active during the day, especially if they feel safe and comfortable in their captive environment. At night, they forage for food, explore their surroundings, play with toys, and engage in other activities.

Moreover, their shy nature urges them to stay hidden from unknown people, surroundings, and mates. If you’re interested in learning more about hermit crabs and their social behavior, I invite you to follow the footsteps of this comprehensive guide dedicated to these fascinating creatures.

Let’s dig into the nocturnal nature of Hermies!

Are hermit crabs nocturnal?

Yes, hermit crabs stay up all night. There is an idiom common in people, “are you a hermit?” It means why you are so shy and stay camouflage all the time. Basically, it’s an idiom curated from facts because hermit crabs are nocturnal.

According to the report of San Francisco Zoo and Gardens, hermit crabs are nocturnal. They love darkness and they enjoy the night. However, it does not mean they do not come out of their homes in the daytime.

They are also active during the day, especially when they are in captivity. However, the condition is if they feel safe and comfortable in their environment. Here, a question pop-up in our minds: why do hermit crabs come out more often at night but not in the daytime.

Let’s answer it in the next section! You could also be interested in watching this YouTube video about how to take care of a hermit crab that they start living a long and happy life without any fear.

Why Hermit Crabs Exhibit Nocturnal Nature?

Here are a few reasons why hermit crabs exhibit nocturnal nature:

  1. Predation Avoidance:

Do you know hermit crabs are like stealth ninjas when it comes to dodging predators? They have mastered the art of nocturnal living to stay out of sight from daytime hunters like birds and fish.

As a result, they reduce their chances of becoming someone else’s dinner. That’s why they stay hidden during the day and only venture out at night.

  1. Competition Reduction:

Imagine a crowded beach party where everyone’s fighting over the last slice of pizza. That’s how it feels for hermit crabs during the day when everyone’s out and about.

But at night, it’s like having the whole beach to themselves! Hermit crabs avoid the chaos and competition for food and space by waiting until everyone else has hit the hay.

  1. Food Availability:

Everybody knows that hermit crabs aren’t picky eaters. However, they know where the buffett’s best at night. Moreover, many tasty treats like insects and decaying plants also come out in the darkness.

This makes it the perfect time for a hermit crab feast. Plus, they can munch on their favorite snacks without having to share with fewer competitors around.

  1. Temperature Regulation:

Hermit crabs don’t like sunbathing on a scorching hot day. In fact, they enjoy a cool breeze at night. In simple words, hermit crabs prefer the latter.

So, they avoid overheating and stay comfortable in their shells. All of this is possible by staying hidden during the day and coming out to play when things cool down.

  1. Activity Adaptation:

Hermit crabs are creatures of the night, plain and simple. They have adapted their lifestyle to fit the nighttime rhythm.

Furthermore, they use their keen senses to navigate the darkness and find whatever they need. So when the sun sets, it’s time for hermit crabs to shine or scuttle around in the moonlight.

  1. Moisture Conservation:

Just like humans reach for a drink when they are thirsty, hermit crabs need to stay hydrated too. The sun can suck up moisture faster than a sponge during the daytime. So… it leaves hermit crabs parched.

They stay hidden in their cozy shelters during the day and come out at night when the air is cooler and more humid. In this way, they hold onto their precious moisture and avoid drying out. It’s important to understand that moisture is very important for their health like in the molting process.

  1. Reproduction Strategy:

Hermit crabs have a cunning plan when it comes to making babies. Many species of hermit crabs release their eggs into the ocean when they live in the wild. Here… they drift with the currents until they hatch into tiny larvae.

When hermit crabs lay their eggs at night, they are playing it smart. In fact, they are giving their babies a better shot at dodging hungry predators who are snooping around during the day by doing it under the cloak of darkness. It’s safer and smarter!

  1. Sensory Advantage:

Hermit crabs have some seriously sharp senses. They put them to good use at night. Interestingly, hermit crabs are like detectives on a mission when the sun goes down.

They do this with the help of their eyes adapted to low light conditions and their antennae finely tuned to detect smells and vibrations. Moreover, hermit crabs move in their environment and locate food and fellows more effectively at night.

Credit goes to their sharp senses!

How many hours does a hermit crab sleep?

Hermit Crab Behavior Nocturnal or Diurnal

According to the study and review of many Quora Digest colleagues, hermit crabs sleep 6 to 8 hours per day. Their sleeping pattern is similar to humans. However, all hermit crabs do not follow this pattern. Instead, they take short rest periods throughout the day and night.

Usually, it lasts for a few minutes to a couple of hours at a time. Thus,the total amount of time they rest or sleep can vary depending on factors like their environment, activity level, and individual behavior.

Do Hermit Crabs Always Sleep in Their Shells?

A hermit crab’s shell is like its own personal fortress. It provides them a shield from predators who would love a tasty crab snack. But when things get too muggy inside, the crab will come out of the shell.

Then, they bury themselves in the sand for fresh breathing. Humid weather gets these crabs buzzing with activity. So, they opt for a snooze outside their shells when the humidity levels spike.


  1. Do hermit crabs sleep all day?

Yes, hermit crabs do sleep all day. If they don’t sleep, they remain hidden in their homes or do a little bit of creative activities.

Moreover, hermit crabs are active during the day if a proper crabitat (hermit crab tank) is given to them. You can watch out this video to set up a proper tank for your hermies.

  1. Is a hermit crab diurnal?

No! Hermit crabs are not diurnal. They are nocturnal and their nature keeps them stay up all night.

However, as I have mentioned before, they are also active in a few parts of the daylight. So while they are not strictly diurnal, they can exhibit activity during both day and night.

  1. Why is my hermit crab not moving at night?

There could be several reasons why your hermit crab is not moving at night. For example:

  • Molting: Hermit crabs periodically shed their exoskeletons in a process called molting. This process lasts for several weeks and they become less active or even stay hidden to protect their soft new exoskeleton until it hardens.
  • Temperature: If the temperature in their habitat drops too low at night, they become sluggish or inactive.
  • Stress or Illness: Hermit crabs can experience stress or illness. It can make them lethargic or inactive. Factors such as sudden changes in their environment, poor water quality, or inadequate nutrition can contribute to stress or illness.
  • Age: Older hermit crabs naturally become less active as they age. Their activity level decreases and they spend more time resting or hiding.
  • Behavioral Variation: Like any living creature, individual hermit crabs have their own unique behaviors and preferences. Some hermit crabs are naturally more active at night, while others prefer to rest or hide during certain times.

It’s essential to monitor them closely and ensure their habitat meets their needs for temperature, humidity, nutrition, and overall well-being.

  1. Is It OK for Hermit Crabs to Sleep in Piles?

This behavior is totally normal for hermit crabs. They are super social creatures.

In their natural habitats, they hang out in big groups, even when they are catching some Z’s. So, it is not a shocking thing to see the same cozy cuddle puddles in domestic crab colonies too.


In summary, we found that the shyer hermit crabs prefer to wait until nighttime to come out and do their thing. Long story short, “The Sun Goes Out, Let’s Party!” Hermit crabs prioritize staying out of the sun during the day due to their soft and thinly-covered abdomens as part of their primary defense.

I chatted with a Key West local who mentioned that all the crabs there emerge at the same time. They make quite a noise as they clink their shells together. They are always on the hunt for food, water, and shells, searching everywhere they can.

If you want to witness your crabs in full swing, I suggest staying up late with the lights dimmed and observing them. Trust me, it’s a fascinating experience you won’t want to miss!