All hermit crabs are born in the ocean, hatched from eggs that burst upon contact with saltwater. Some remain in the sea, and others make their way to land.
Marine hermit crabs must remain underwater. They occasionally head to the shore, looking for food, but only for a while. Too much time out of the water makes their gills close up, leading to suffocation.
Terrestrial hermit crabs can breathe on land as long as they remain in humid conditions and keep their gills moist, but they can’t breathe underwater. A land hermit crab will drown if left in the water and unable to escape.
Do Hermit Crabs Live in Water or on Land?
Hermit crabs live on land and underwater, but never at the same time.
Most hermit crabs are aquatic animals that need to live in water to breathe. However, many pet species of hermit crab are terrestrial.
Aside from occasional interactions on the shore of a beach, they never interact in the wild. Land-based hermit crabs will head into the sea to birth their young, mate, or bathe. Marine hermit crabs, meanwhile, occasionally visit dry land to seek food.
In captivity, aquatic hermit crabs need to spend their time in an aquarium, while their land-based counterparts can’t be submerged in such a large body of water.
How Long Can Hermit Crabs Stay Underwater?
Aquatic hermit crabs can spend their entire lives underwater. If food is plentiful beneath the surface, a marine hermit crab doesn’t need to venture onto dry land.
For terrestrial hermit crabs, this is a different story. Land-based hermit crabs need humidity and drinking water to keep their gills moist but rely on carbon dioxide to breathe.
While terrestrial hermit crabs periodically immerse themselves in water, they hold their breath while they do so. No hermit crab can hold its breath indefinitely, and if it can’t escape the water, it’ll drown.
Most healthy adult hermit crabs can hold their breath for around 30 minutes. Wild terrestrial hermit crabs will visit the ocean quickly, then return to land.
In captivity, hermit crabs will submerge in water and periodically arise to take a breath.
How Long Can Hermit Crabs Live Out of Water?
Marine hermit crabs aren’t as reliant on water as fish but aren’t far off.
Marine hermit crabs can only survive on dry land for a while. If out of water for too long, marine hermit crabs are at significant risk of suffocation.
Aquatic hermit crabs breathe in oxygen found in the water. This is drawn to the gills by the scaphognathite, an appendage found below the mouth. Once oxygen is processed through the gills, it’s passed through the blood, and CO2 is expelled through the mouth.
A marine hermit crab that has spent too much time on dry land will start blowing brown bubbles. This is a sign of stress, typically suggesting the hermit crab is seriously dehydrated and in need of water.
Unless the hermit crab returns to the water soon, it’ll perish.
How to Tell Land and Marine Hermit Crabs Apart
Visually, there’s little difference between marine and terrestrial hermit crabs. Both have ten legs, and neither is born with a shell, so they’ll commandeer a vessel from another animal, typically a mollusk.
Marine hermit crabs are likelier to have decorative features on their legs, such as stripes or spots. Most terrestrial hermit crabs are one color.
Aquatic hermit crabs may also have a sea anemone attached to their shell. As discussed by Helgoland Marine Research, they enjoy a symbiotic relationship. Anemones protect hermit crabs from predators, while the hermit crab will share food.
The easiest way to tell marine and terrestrial hermit crabs apart in the wild is where you find them. Aquatic hermit crabs will never venture far from the shore and are unlikely to be found on the beach when the tide is low.
Where Do Wild Hermit Crabs Live?
Hermit crabs are usually found on beaches. The most significant populations of wild hermit crabs are located in the western Atlantic territories, the Caribbean, Africa, Australia, and the Indo-Pacific region. These areas offer the climate that hermit crabs need to flourish.
A handful of terrestrial hermit crabs can be found in the USA, particularly in territories with beaches that border the Atlantic. The Florida Keys, for example, is a common home for hermit crabs, though the Chesapeake Bay is also heavily populated by these animals.
Do Hermit Crabs Live in the Ocean?
The ocean is where most hermit crabs, discovered by humans or otherwise, will be found. Most hermit crabs stick to the ocean floor in the deepest part of the sea, though some will hide in coral reefs in shallower waters.
There are many potential predators for marine hermit crabs, most notably countless species of fish. Hermit crabs prefer to remain at the bottom of the sea, where enemies are less prevalent.
Terrestrial hermit crabs occasionally visit the ocean but cannot live underwater. However, all hermit crabs are born in the sea. Hermit crabs hatch as larvae known as zoeae, with those that survive long enough evolving and moving to dry land after two months.
Can Hermit Crabs Live in Freshwater?
Only one hermit crab species, Clibanarius fonticola, is known to live in freshwater.
This hermit crab is found in Espiritu Santo, the largest island in the Republic of Vanuatu. As per the Journal of Crustacean Biology, this species was discovered in 1990.
If you wish to see one with your own eyes, you’ll need to visit the small village of Matevulu. Clibanarius fonticola lives in pools of water in this area.
Shell selection is limited for this hermit crab, so it’ll invariably use shells previously occupied by Clithon corona, a freshwater snail found throughout the Asia-Pacific region.
Do Marine or Land Hermit Crabs Make Better Pets?
This depends on what you are looking for from your relationship with your hermit crabs.
Marine hermit crabs can help keep a tank clean by eating naturally occurring algae if you keep fish, which are compatible with hermit crabs.
Marine hermit crabs won’t be quite as interactive as terrestrial hermit crabs.
While handling should always be limited for any hermit crab, those that live on land can spend time outside a habitat. Marine hermit crabs need to stay underwater at all times.
Aquatic marine hermit crabs could be considered higher maintenance, as you’ll need to regularly heat and change the water in an aquarium. They can be more decorative, as many marine hermit crabs boast striking colors.
Avoid taking on just one if you adopt marine or terrestrial hermit crabs. These social animals quickly grow bored and depressed if forced to live alone. Ideally, a captive colony of hermit crabs should number at least four or five.
Caring for Marine Hermit Crabs
Marine hermit crabs must live in saltwater, so if you pair them with fish, keep this in mind. Popular freshwater fish, like the betta, aren’t appropriate tankmates for hermit crabs.
The water must meet these criteria if you wish to create an aquarium of hermit crabs:
| Water Temperature | 72OF – 78OF |
| Water pH | 8.0 – 8.4 |
| Water KH | 150 – 215 |
| Water Hardness | 8 – 16 dH |
| Water Gravity | 1.021 – 1.028 |
Also, remember that aquatic hermit crabs can’t be out of the water for long. You’ll need a second tank to host them while cleaning and replacing the water in their primary residence.
Caring for Land Hermit Crabs
Terrestrial hermit crabs have an erroneous reputation as easy pets to care for. While they need less intense attention than a cat, dog, or rabbit, hermit crabs still need and deserve high care.
If you bring terrestrial hermit crabs into your home, you’ll need the following.
- A tank of at least 10 gallons, bigger if you take on more than six hermit crabs.
- No less than six inches of substrate for the hermit crabs to burrow, hide, and sleep under.
- Entertainment within the tank, such as climbing apparatus.
Most importantly, a terrestrial hermit crab habitat must be heated to around 80OF and operate at a humidity level of 80%. Anything less and the hermit crabs’ lives will be at risk.
