21 Interesting Facts about Hermit Crabs
We see hermit crabs for sale in beach gift stores and pet shops, and crawling around beaches and island mangroves, but how much do you know about these little fascinating, quirky little creatures?
1. Hermit crabs are not true crabs
2. Some hermit crab species can live up to 30 years
Hermit crabs can live for up to 30 years, depending on the species, if they are well cared for. Hermit crabs have a relatively long lifespan for their size.
3. They have soft abdomens that MUST be protected by a hard shell
Unlike true crabs, hermit crabs have a soft, asymmetrical abdomen that must be protected by a shell. They use discarded shells of other sea creatures as their homes. See my article on Hermit Crab Shells for more information on the anatomy of hermit crabs and what’s inside the shell, and best types of shells for hermit crabs with photos.
4. Hermit crabs are SOCIAL and prefer living in groups
5. They molt their exoskeleton periodically
A crucial part of a hermit crab’s life cycle is periodic molting where it will burrow in sand or substrate for a period of time in order to shed their exoskeleton.
6. They eat their exoskeleton while molting!
During the molting process, hermit crabs will eat their shedded exoskeleton which helps sustain them while they are in this weakened state. Here’s more information on hermit crab molting, here.
7. Hermit crabs are scavengers and omnivores
Hermit crabs are omnivores, eating both plants and animals. They feed on coastal vegetation, small animals like worms and snails, washed up algae, plankton, fish and shrimp and love a wide variety of foods including fruits, vegetables, nuts and grains, meats, seafoods and… they enjoy snacking on shredded coconut and popcorn! Here’s lots more information on nutritional needs, food lists and ideas in my article Hermit Crab Food here.
8. Yes, Hermit Crabs DO SEE... (but not like we do)
9. Hermit crabs do NOT swim!
They are not swimmers. They like to wade into the water slowly and gently, on their own terms. They do not like to be placed underwater, or rolled into the ocean by crashing waves. Hermit crabs prefer safe tidal pools and very calm lagoons when crawling along the ocean’s edge. For hermit crab pets, it’s important to provide optimal water conditions and opportunities for a good bath… here are tips, ideas and photos on hermit crab water requirements and tips here.
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10. Hermit crabs can be territorial
Despite being social creatures, hermit crabs are territorial and will fight to defend their homes when they feel threatened. They use their claws to pinch and intimidate rivals. Territorial behaviors, when in captivity, most often come from several possible scenarios: lack of extra shells, enclosure too small for number of hermit crabs, food/variety lacking. See my article on hermit crab bullying here, for more tips and ideas on how to avoid territorial behavior in hermit crab pets.
11. Hermit crabs DO sleep and also take naps!
Hermit crabs are nocturnal, so they can be quite active at night. They are known to sleep 8-10 hours most days, and they also take naps! How do you know when they are sleeping? Generally they sit inside their shells, halfway in and halfway out, with the top of their shell sitting over their heads and legs out. When they hear (or sense or feel) a sound or something approaching, they will wake up fairly easily. See my article Do Hermit Crabs Sleep, here.
12. Hermit crabs are nocturnal
Hermit crabs are nocturnal creatures and are most active at night. During the day, they take naps and burrow or hide in dark spots away from potential predators. Find more information on hermit crab behaviors including nocturnal activities in my article Hermit Crab Behaviors here.
13. Hermit crabs need extra shells
Hermit crabs must change shells as they outgrow their current one or if it becomes damaged. They will search for a new shell that fits them and move in, so it’s very important for hermit crab pets to have a variety of extra shells available at all times to try on and eventually move into.
14. Hermit crabs CAN BE PICKY about shells
There is a misconception that hermit crabs are not picky about their shells. This comes from a few rare photos of hermit crabs wearing bottle caps or plastic bottles as shells. However, these photos were most likely a result of a lack of suitable shells, and the hermit crab had not choice but to use what he could to protect his soft, moist abdomen to survive. Hermit crabs ARE generally picky about their shells, trying on multiple shells until they find the right fit, weight and shape they like best. Did you know? Caribbean (Purple Pincher) hermit crabs LOVE turbo shells especially as the older and bigger they get? See my article on Turbo Shells here for more information and the many beautiful types of turbos available!
15. They LOVE TO CLIMB!
Hermit crabs are excellent climbers and can climb trees and other vegetation near the ocean. They use their claws to grip onto branches and leaves, and will often take naps during the day while clinging to wood or rock (or the mesh screen on top of their hermit crab habitat!) with their pincers. Looking to add some fun and stimulation to your hermit crab habitat including opportunities for more climbing… see my article to get more ideas and photos here: Hermit Crab Habitat Fun and Stimulation.
16. They can regenerate limbs
Hermit crabs can regrow legs, claws, and even antennae when they get damaged or broken due to a fall or fight, which is all a part of the challenging life of a hermit crab.
17. They breathe air but have gills like a fish?
They have an adapted form of gills, which means they breathe air but still need moisture on their gills in order to survive. They must be able to submerge in water enough to collect water in their shell, to conserve moisture for protecting their abdomens and also drinking while going without water during molting.
Humidity levels play a large role in making sure a hermit crab’s gills remain moist in order to breathe.
Some species of hermit crabs require more moisture on their gills, more humidity in the air they breathe than others, more saltwater than freshwater, etc.
For this reason, the Caribbean (Purple Pincher) hermit crab is generally considered the easiest of all hermit crab species to keep happy and healthy in captivity.
For more information, see my article on How Do Hermit Crabs Breathe on Land, here.
18. Hermit crabs are found along ocean coastlines all over the world
Hermit crabs are found living on the edge of oceans across the world, with anywhere from 500-800 different species known. This number is disputed among experts, as many places around the world where hermit crabs live are remote, and many species remain unstudied. There are 10 most common hermit crabs found within the pet industry across the world, including the Caribbean (Purple Pincher), Ruggie, Strawberry, Blueberry, Indo and Eccie. See my article Types of Hermit Crabs, for the 5 most common hermit crab pets found around the world, with photos.
19. The Coenobita clypeatus is the most common hermit crab pet
The Coenobita clypeatus, commonly known as the Caribbean hermit crab, the Purple Pincher, Tree Crab and Soldier Crab is the most common hermit crab species within the pet industry, and most especially in the U.S. They are considered to be the most adaptable hermit crab species to captivity, often living over 20 years when well-care for. For my article on Purple Pincher hermit crab care, here.
20. Hermit crabs are found in a variety of coastal habitats
Hermit Crabs can be found in various coastal habitats, including sandy beaches, rocky shores, mountainous coastlines, mangroves and coastal forests.
21. Hermit crab reproduction is complicated, long and arduous and has rarely happened in captivity!
Very rarely have hermit crabs reproduced in captivity, as they need the ocean for tiny hatchlings to be sent out into the ocean and develop before eventually washing back onto shore and making the miraculous transformation into a land creature like their parents. To reproduce in captivity a very specific set of conditions and processes need to be set up in order to mimic the life cycle of hermit crabs from eggs to land hermit crabs and all the stages in between.
Last update on 2024-05-08 / Affiliate links / Images from Amazon Product Advertising API