Home | Reptile and Amphibian Health | feeding and diet | Land Hermit Crabs and Coconut Crabs (the world’s largest) as Pets

Land Hermit Crabs and Coconut Crabs (the world’s largest) as Pets

Coconut CrabHello, Frank Indiviglio here.  People are often surprised to learn that Land or Terrestrial Hermit Crabs engage in complex social behaviors, are capable of communicating via “chirps” and, with proper care, may live for over 20 years.  I’ve had the pleasure of working with them at home, in zoos and the wild, and have even kept the massive, awe-inspiring Coconut Crab.  Please read on to learn about their care and natural history, and be sure to post your own thoughts and experiences.

Natural History

The Purple-Pincher or Caribbean Hermit Crab (Coenobita clypeatus) is the most common pet trade species.  It ranges throughout the Caribbean, reaching as far north as Florida and Bermuda. 

Some populations live at altitudes of over 3,000 feet, but females return to the sea, usually in one massive migration, to spawn. The larvae, or zoea, float about with plankton for 2 months, after which they take up life on land.

Land Hermit Crabs carry about the discarded shells of other creatures as shelters, and must find larger shells as they grow.  Recently it was discovered that they will line up in size order behind an empty shell – as the first crab (the largest) moves into its new home, others in line will “trade up” for the shell of the crab immediately in front of them!  Please see the article below for details.

Ecuadorian Hermit Crabs (Coenobita compressus) and several Asian species also appear in the pet trade.  The Coconut Crab (Birgus latro) is sometimes kept within its native range.

Behavior

Land Hermit Crabs are nocturnal, but pets often emerge to feed by day. When established in a properly-designed terrarium, they will be quite active and exhibit many interesting behaviors.

Handling is stressful to Hermit Crabs, including long-term pets.  They can be grasped by the back of the shell, but often can reach this area with their claw. Large individuals can administer a painful pinch, and I’d bet that the Coconut Crab can break fingers!

Housing

Setting up the Terrarium

Hermit CrabA 10 gallon aquarium will accommodate 4-5 small crabs.  Large, naturalistic terrariums will allow the crabs to exhibit a wider range of behaviors than will small, bare enclosures. 

Driftwood, cholla wood, reptile caves, up-ended clay flower pots and similar furnishings will add greatly to your crabs’ quality of life.  Empty shells should always be available.

A molting tank should be set up if you keep more than one crab.  Land Hermit Crabs are soft and defenseless after molting, and will be eaten by their former friends.  Check daily for signs of an impending molt – digging, remaining below ground and listlessness are typical.  Molting crabs should be isolated (please write in for information). 

Substrate

A mix of calcium sand and coconut husk makes an ideal substrate.  The substrate should be at least 6 inches deep and mixed with enough water so that is just sticks together when squeezed. 

Light

Red/black reptile night bulbs will allow you to watch your crabs after dark.  A 12-hour day/12 -hour night cycle is ideal.

Heat

A temperature range of 75-82 F should be maintained.  These tropical creatures will not survive long term exposure to temperatures below 72 F.

Incandescent bulbs or red/black reptile night bulbs can be used to heat the terrarium.  Ceramic reptile heaters are useful at night.  Reptile heat pads can be used to warm the substrate, but these do little to heat the air.  All of the above will dry out the substrate, so it is important to monitor the humidity.

Humidity

Land Hermit Crabs possess unique gills that enable them to breathe air.  A humidity level of 70-80% is vital to survival, as the gills must be kept moist in order to function.  A simple humidity meter should be used.  Humidity can be increased by misting, adding water to the substrate and partially covering the terrarium’s lid with plastic. 

Companions

Hermit CrabLand Hermit Crabs are social animals, but dominant individuals may prevent others from feeding properly.  Crabs that are molting must be isolated or they will be attacked (please see above).  A variety of empty shells must be available, or fighting and “evictions” will ensue.

Feeding

Wild Hermit Crabs eat just about everything – animal, vegetable and mineral – that they encounter.  Captives will not thrive without a varied, high-calcium diet.

Commercial Hermit Crab pellets may be used as a portion of the diet.  The following foods should be included regularly: fresh shrimp and fish, fruits and vegetables (carrot may help to maintain coloration), hard-boiled egg, nuts, seeds, dry seaweed (sold as Nori), oatmeal, fish flakes, canned crickets, and freeze-dried fish foods (krill, plankton, brine shrimp, etc.).  They also relish decaying wood and leaf litter; these should be collected from pesticide-free areas. 

Cuttlebone bits and reptile calcium powder should be mixed into your crabs’ food.

Often overlooked is their need for a bowl of marine water; marine aquarium salt mixes, not table salt, should be used.  Soaking in this water will provide the crabs with essential minerals not present in their food.  Fresh de-chlorinated water should also be available.  Bowls should be filled to half the height of the smallest crab and be easily-exited, as Land Hermit Crabs drown easily.

A wide variety of specialty cages, supplies and foods are now available.  Please post any questions or comments you may have regarding their use.

The Coconut or Robber Crab (Birgus latro)

With a 16 inch body supported by legs spanning 3 feet, this impressive beast (described as “monstrous” by Charles Darwin!) is the world’s largest land-dwelling arthropod. I first saw them at the Cincinnati Zoo Insectarium in the early 1980’s, and was instantly hooked.  After a prolonged search, I obtained 2 adults for an exhibit at the Bronx Zoo. Unfortunately, they did not fare very well, and this seems to be a common experience (wild individuals may attain age 40+).  Losses are especially high during the month-long molt, which is spent underground.

Hermit CrabThe Coconut Crab ranges throughout the Indian and Western Pacific Oceans. A co-worker of mine found them raiding his garbage cans on Guam; his experiences with refuse-feeding coatis and coyotes elsewhere in no way prepared him for that! 

Coconuts may be their best-known food, but form only a small portion of the diet. Generally, the crabs pinch nuts from coconut palms, and then feast on the broken remains below.  A crab may also pull back the husk from an unbroken coconut and then pierce the soft “eye” with one of its pointed legs. The rest of the diet is as varied as that of their smaller relatives.

Coconut Crabs are declining in portions of their range. Threatened by food trade collection and predation by introduced rats, ants, pigs and monkeys, they have been extirpated from Australia and Madagascar. 

Please check out my posts on Twitter and Facebook.  Each day, I highlight breaking research, conservation news and interesting stories concerning just about every type of animal imaginable.  I look forward to hearing about your interests and experiences as well, and will use them in articles when possible.

 

Please also post your questions and comments below…I’ll be sure to respond quickly.  

Thanks, until next time,

Frank Indiviglio

 

Further Reading

Hermit Crab “Shell Trading” Behavior

Coconut Crab Video

Natural History of Land Hermit Crabs on Bermuda

 

Coconut Crab image referenced from wikipedia and originally posted by Anne Sheppard

 

10 comments

  1. avatar

    Thanks for posting. I currently have a hermit crab setup with two in there. i notice one has been digging an aweful lot and I am glad to know that it may be a pre molt. They are pretty big land hermit crabs and I do not know what size shells to get.

  2. avatar

    Hi Ariel,

    Thanks for the feedback;

    Be sure that the substrate is deep enough to allow for burrowing, and provide a few shells that are slightly larger (internally) than the current shell, Best, Frank

  3. avatar

    Thanks for the share. I think if anyone purchase shells, the shell should be a size bigger than the previous size. But much bigger size will not be beneficial, as the crabs always tries to find the previous shell’s feel in the later ones. So much bigger or designed shells will not provide any added advantage according to me.

  4. avatar

    Hi,

    Thanks for your input. Yes, always best to provide as wide a variety as possible; in the wild, I’ve seen them make due with ill-fitting shells (and discarded plastic,etc!) but in captivity its best to let them try out a few when changing shells. Best, Frank

  5. avatar

    I’ve seen coconut crabs at Japanese pet stores and they truly are a sight to behold!

    I think the housing would require too much effort, but they do seem like an interesting pet to keep :)

  6. avatar

    Hi Paul,

    Thanks for your note. Since childhood, I’d been fascinated by the interest Japanese people show in invertebrates (being bug-crazy in the Bronx, way back then, was not “typical”, shall we say!). I eventually managed to spend some time there, after making contacts through the zoo field. I was astonished at the insect exhibits in zoos, pet trade interest and so on (public aquariums, and pet trade fishes, were also amazing). I never ran across coconut crabs…thanks for letting me know. Do you happen to remember the price range…I recall that we (Bx Zoo) paid $600.00 each in 1985.

    Did you have a chance to visit any insect exhibits, i.e. at the Tama Zoo, or aquariums? I can’t wait to go back.

    Best regards, Frank

  7. avatar

    Yeah, Japan does have a big fascination with insects. Two weeks ago I went to a Reptile/Insect show in Tokyo and it was definitely interesting :)

    I’ll check the price next time I happen by that pet store. It’s a very large one in Yokohama that carries a range of exotic pets which change regularly. If I were rich I’d pick up the armadillo they’re selling for $3,000. They also have a miniature pig and small monkey. Have also seen prairie dogs and meerkats on sale as well. Very startling array of pets for a Minnesotan like me to encounter.

    I think one of most fun bug exhibits I’ve seen was in Penang, Malaysia at the Butterfly Farm. Went there in August, had a blast.

  8. avatar

    Hi Paul,

    Thanks very much for the note, you’ve ignited my desire to return. I visited an impressive aquarium in Yokohama about 5 years ago, name escapes me now…entry was up a long ramp, then you worked your way down, I believe. Was especially surprised b some of the deep sea inverts they were able to keep.

    My Mom was fascinated by Japan when I was a child…odd, as she was WWII generation and we lived in the Bron, sans any Japanese influence. But she had me join the Japan Society in Manhattan, learned a bit of the language and so on. Once I learned about their interest in insects, my interests really took off. Even as late as the 80′s, when I was setting up invert ehibits for the B Zoo, the best sources of books and info were in Japan.

    I’ve worked with armadillos…very interesting beasts, and they seem to draw invert-herp enthusiasts I’ve noticed. Always surprised by the value of animals in the trade; 9 banded armadillos are feral in the SE USA, garden pests in many places! I recall many years ago a hep dealer I worked for shipped some leopard frogs (used as lab animals at the time) to Japan, as a freebie along with animals that had been ordered. The dealer asked as to sens as many as possible, and offered to pay very well…

    Please keep me posted when you have time..I’m planning a few related articles and would appreciate being able to use some of your observations. Are you living there permanently? If so’ I’ll touch base when I visit. Best, Frank

  9. avatar

    That’s quite interesting, didn’t even know there were Japan Societies!

    I’ll be starting a reptile blog which is focused on providing locations of pet stores and event info in English for those who live in Asia. Starting out first with just Japan but I would like to expand later.

    If you want to keep in touch you can add me on Facebook: http://www.facebook.com/paul.franz.925

  10. avatar

    Hi Paul,

    Thanks…very good to hear, I wish you well. I’ll keep tabs on Facebook, but I don;t get a chance to do so all that often. I’m on FB at http://www.facebook.com/frank.indiviglio.9, my email is findiviglio@thatpetplace.com. If you have a chance, please send an email or post a note on any blog article so that other readers can benefit as well, thanks.

    Japan Society, Nippon Club (business oriented) and the Asia Society have long been in Manhattan, along with many smaller institutions. Although a grew up a “world” away culturally (in the Bronx), a quick train ride took me to all, as well as the Am Museum of Nat History, etc…I was very fortunate, as my family encouraged that as well.

    Just rec’d a note that a fish importer in Miami is selling Australian Lungfish; have you seen them in aquariums or pet trade? I saw them at several zoos/aquariums in Japan..unbelievable, easy to picture one crawling out of the water and starting down the path to a terrestrial existence. I was surprised to see them munching on chopped plantains; the African/SA species I’ve kept were strict carnivores, but then again they are very different animals… Enjoy, Best, Frank

Leave a Reply

Your email address will not be published.

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>

About Frank Indiviglio

Read other posts by


avatar
Being born with a deep interest in animals might seem unfortunate for a native Bronxite , but my family encouraged my interest and the menagerie that sprung from it. Jobs with pet stores and importers had me caring for a fantastic assortment of reptiles and amphibians. After a detour as a lawyer, I was hired as a Bronx Zoo animal keeper and was soon caring for gharials, goliath frogs, king cobras and everything in-between. Research has taken me in pursuit of anacondas, Orinoco crocodiles and other animals in locales ranging from Venezuela’s llanos to Tortuguero’s beaches. Now, after 20+ years with the Bronx Zoo, I am a consultant for several zoos and museums. I have spent time in Japan, and often exchange ideas with zoologists there. I have written books on salamanders, geckos and other “herps”, discussed reptile-keeping on television and presented papers at conferences. A Master’s Degree in biology has led to teaching opportunities. My work puts me in contact with thousands of hobbyists keeping an array of pets. Without fail, I have learned much from them and hope, dear readers, that you will be generous in sharing your thoughts on this blog and web site. For a complete biography of my experience click here.
Scroll To Top