People assume that hermit crabs live short lives. While pet hermit crabs that were bought at seafront shops rarely live longer than a few weeks, this is not the natural lifespan of hermit crabs. Hermit crabs can survive for decades.
The oldest recorded hermit crab survived to 40. In the wild, hermit crabs often live for 30+ years. This assumes the hermit crab evades predators and environmental hazards. A well-cared-for pet hermit crab could live just as long.
Many hermit crabs die in captivity for avoidable reasons. If you want to care for hermit crabs, you’ll need to take the time to understand which factors affect longevity.
Hermit Crab Life Cycle Explained
The life cycle of a hermit crab is unique and undeniably fascinating. As with all animals, it begins with breeding and insemination. It is possible to breed hermit crabs in captivity but challenging. Most hermit crabs are stressed in captivity and unwilling to breed.
Hermit crabs then hatch from eggs and live in the sea as larvae. If they survive this experience, they evolve into juvenile hermit crabs. Those lucky enough to live long enough become adult hermit crabs. From there, they may live for decades.
Breeding and Gestation
As per the Journal of the Marine Biological Association of the United Kingdom, hermit crabs breed when young. Females typically birth before one year of age. This ensures the female can find a plentiful supply of small shells. Pregnancy freezes growth in hermit crabs.
Mating occurs in the spring or summer. Following a successful mating, a female hermit crab lays thousands of eggs. These are carried in the pleopods – the legs on the left of a hermit crab’s body.
After around a month, these eggs matter. They change in color from red to gray at this point. When ready to hatch, the hermit crab tosses the eggs to sea. Upon contact with saltwater, the eggs burst open. A baby hermit crab, or zoea, is born.
Zoea and Megalopa
Zoeae are free-swimming larvae that float alongside plankton in the ocean. At this stage, a zoea may become a whale snack. Alternatively, the zoeae may cannibalize each other.
If it survives for around 60 days, the zoea evolves into a megalopa. This is a primitive life stage that resembles a cross between hermit crab and lobster. The megalopa is still tiny, typically smaller than a fingertip.
The megalopa life phase lasts around 30 days. Over this period, the megalopa spends less time underwater. A megalopa has a soft, vulnerable underbelly, so it patrols the shore seeking its first shell. This could be as small as a bottle top at this age.
Juvenile Hermit Crab
Eventually, the megalopa will bury itself under sand and molt. When it emerges, the megalopa has evolved into a juvenile hermit crab. The crustacean now needs a shell and sustenance. It has also developed lungs and modified gills, so it must live on land.
At this point, the hermit crab is at its most vulnerable. Juvenile hermit crabs constantly outgrow their shells. This means they need to regularly find replacements. This, naturally, involves foraging. The juvenile may be picked off by predators while unprotected.
Marine Environmental Research explains that predators are a major hazard to juvenile hermit crabs. Unfortunately, juvenile hermit crabs need a balance of natural light and darkness. Hiding under the sand 24/7 is not an option. This stifles growth.
The scent of dead crustaceans will attract juvenile hermit crabs. This is not an act of willful cannibalism, though they will scavenge any dead carcass. Rather, this odor suggests that a shell is vacant.
Adult Hermit Crab
It can take up to two years for a hermit crab to reach full maturity. If the hermit crab survives this long, it is typically quite savvy. The hermit crab will understand the risks of life in the wild. It will adapt its lifestyle accordingly.
Adult hermit crabs can live for up to 30 years – or even longer – in the wild. Hermit crabs are omnivorous but survive by scavenging. Hermit crabs eat live insects. They are likelier to survive on seaweed, algae, and dead animals, though.
Adult hermit crabs are also just as susceptible to stress and an inappropriate environment as juveniles. Capturing an adult crab is not a guarantee of hardiness. Adult hermit crabs may live ten years but die within a month of captivity. Appropriate care is critical.
How Long Can a Hermit Crab Live Without Food?
As hermit crabs have such tiny bodies, they can survive around two weeks without food. Overall though, regular eating is a good thing. Eating often and heartily is a sign that a hermit crab is happy and comfortable. Hermit crabs are likelier to fast when stressed.
Hermit crabs eat more ahead of a molt. This is the hermit crab stocking up on fat. Hermit crabs do not eat conventional food while molting. They sustain themselves on their discarded exoskeleton. This process could take weeks or even months.
If you are leaving hermit crabs alone for a prolonged period, leave dry food. Hermit crab food mustn’t spoil. Coconut, nuts, cereals, or seeds are fine. Leave a cuttlebone, too. You could consider hermit crab pellets, but some crustaceans reject these.
How Long Can a Hermit Crab Live Without Water?
You may rarely, or even never, see your hermit crab drink. Despite this, hermit crabs require a constant source of water. Without fresh and seawater, hermit crabs will not survive longer than two weeks.
Hermit crabs need water to retain moistness in the gills. You should offer both fresh water and saltwater to these crustaceans. The hermit crab will choose which water source it needs.
Hermit crabs submerse themselves in this water from time to time. Ensure it can escape, as hermit crabs can drown. During this submersion, the hermit crab drinks. In addition, it stores water in a shell. This ensures the hermit crab has water whenever needed.
Water Sources for Hermit Crabs
Never offer a hermit crab tap water. This contains chlorine, which is toxic to hermit crabs. It can kill these crustaceans on the spot. Use filtered water, or to be safe, bottled water.
As per Animal Behavior, hermit crabs become confused and disoriented by a lack of sea water. This also requires care. Never pour table salt into standard water. This contains iodine, which is just as dangerous as chlorine.
You can get this from a pet store. Alternatively, grind sea salt into pure fresh water. It is best to buy this salt from an exotic pet store. Sea salt purchased from a supermarket may have been treated with unsafe chemicals.
Wild Hermit Crab Life Expectancy
Wild hermit crabs may live for decades. The oldest hermit crab on record was believed to survive to the age of 40. Most long-surviving hermit crabs live for around 30 years. There are two dangers.
Predators of Wild Hermit Crabs
Hermit crabs are not high on the food chain. Multiple species of fish and octopi feed on hermit crabs. Thankfully, adult hermit crabs spend more time on land. This minimizes the risk of exposure to marine predators. The hermit crab only needs to worry when bathing.
Life overground is not entirely safe, though. The hermit crab is not actually a crab. Genuine crabs commonly feed on hermit crabs. Equally, birds may swoop and pluck an exposed hermit crab. This is why these crustaceans burrow when not protected by a shell.
Hiding is the best form of defense for a hermit crab. It will retreat into its shell, hoping a predator cannot break through. If attacked, a hermit crab may sacrifice limbs and flee. These appendages grow back eventually.
Another form of protection for wild hermit crabs is the sea anemone. These animals form symbiotic bonds with hermit crabs. They live atop a hermit crab shell and share food. If the hermit crab is attacked, the sea anemone retaliates with poisonous tentacles.
Environmental Hazards to Wild Hermit Crabs
In addition to wild predators, hermit crabs can be killed by environmental factors. Drowning in periods of high tide is a risk. Most hermit crabs will burrow to avoid this. If caught up, though, the hermit crab will run out of breath.
A bigger concern is litter. Hermit crabs are constantly looking for new shells. This quest can lead to mistaken identity. As per the Journal of Hazardous Materials, hermit crabs often climb inside plastic bottles. They are unable to escape these vessels, dying as a result.
Captive Hermit Crab Life Expectancy
Hermit crabs have a reputation as disposable pets for children. Many people buy hermit crabs from seafront gift shops as souvenirs. When the crab dies after a week or two, little thought is given to it. People assume this is just what
There are many reasons why hermit crabs in captivity die. It is essential to understand the risks of keeping these crustaceans as pets. A hermit crab dying is not ‘just one of those things.’ There will always be a reason for the demise of the crustacean.
Common Causes of Pet Hermit Crab Death
Pet hermit crab fatalities have a wide array of potential causes. Thankfully, they can be avoided. You need to understand the many and varied reasons why captive hermit crabs die. These include:
- Stress – the stress of rehoming can be fatal to hermit crabs
- Drowning – inability to escape a water bath
- Toxicity – breathing in fumes, consuming paint chips or drinking tap water
- Suffocation – lack of sufficient humidity in the habitat
- Infection – unsanitary living conditions leading to bacteria or fungi
- Impact injuries – falls while climbing or being dropped during handling
- Animal attacks – attacked by a fellow crab or another pet while exploring
- Mutilation – some owners mutilate molting hermit crabs believing them to be dead
This is not an exhaustive list. You will need to ensure you meet the needs of a hermit crab. With appropriate care, captive hermit crabs can live as long as their wild counterparts.
How to Make Your Hermit Crab Live Longer
To keep your hermit crab alive for a prolonged period, you’ll need three things.
To elaborate on this further, take a look at the table below. This will detail how you can help a hermit crab flourish in captivity. Meet all these criteria, and a pet crustacean can survive into dotage:
|Bathing||Bathing cleans shells and stores water for the molting period. Ensure the crab can escape. Hermit crabs cannot breathe underwater indefinitely.|
|Calcium||Hermit crabs need calcium to flourish. This toughens up their exoskeleton. Cuttlebone is an optimum source of calcium.|
|Cleaning||Spot clean a habitat daily, removing any dirt, waste, or uneaten food. Replace substrate periodically and perform occasional deep cleans.|
|Company||Hermit crabs are social and live in groups in the wild. Consider the addition of additional hermit crabs to a habitat.|
|Decorations||If you wish to enliven an aquarium, avoid shop-bought decorations. The heat and humidity can make toxic paint and dye run.|
|Destressing||If your hermit crab seems distressed, think why. Consider moving the aquarium to another, quieter location.|
|Diet||As scavengers, hermit crabs have a varied diet. Never feed the same thing twice in two days. Keep food interesting and diverse.|
|Fumes||Be mindful of fumes, such as aerosols caused by deodorants or air fresheners. These can choke a hermit crab’s tiny lungs.|
|Handling||It’s fine to handle a hermit crab on occasion. This will help the crustacean build trust in you. Do not handle to excess, though.|
|Hiding Places||Life in captivity can take some getting used to. Ensure the hermit crab has plenty of places to hide. Rocks and logs are fine.|
|Humidity||A hermit crab aquarium must always remain at 80% humidity. Purchase a humidity gauge to ensure this. Use a misting spray if necessary.|
|Light||Hermit crabs are nocturnal, so do not expose them to too much light. Natural daylight is fine if there is an appropriate day/night contrast.|
|Noise||Try to avoid placing a hermit crab in noisy rooms. This will cause stress and overstimulation.|
|Privacy||If your hermit crab has burrowed, leave it alone. Never dig up or disturb a burrowed crab unless it’s an emergency.|
|Protection||Hermit crabs are delicate. Do not drop your crab. If you let it explore the house, protect the crustacean from falls and other pets.|
|Recreation||Make life fun for a hermit crab. Provide the opportunity to dig or climb safely. This will imitate a wild lifestyle. ShellsOffer the hermit crab a variety of shells in different shapes and sizes. This will help the hermit crab feel more secure.|
|Space||Hermit crabs are used to roaming free. Ensure a habitat offers enough space. An aquarium should be 10 gallons in size, minimum.|
|Substrate||Pack a minimum of 3 inches of soft sand into a habitat. Hermit crabs love to burrow. Avoid calcium sand, as this stiffens a hermit crab’s joints.|
|Temperature||Never let a hermit crab habitat drop below 80 degrees Fahrenheit for any prolonged period. Use a heat lamp if required.|
|Water||Offer a hermit crab a choice of fresh and saltwater for bathing and hydration. Never use tap water. Chlorine is toxic to hermit crabs.|
Upon bringing a hermit crab home, focus on the basics. The first few weeks are critical. You may not see much of your hermit crab. If it burrows underground, leave it be. The hermit crab is destressing. It will re-emerge when it feels ready.
If you meet fundamental needs at this point, you can keep your hermit crab alive. After that, you can add flourishes to its habitat. Over time, you will bond with your hermit crab and develop an owner-pet dynamic.
Under the right conditions, hermit crabs outlive many domestic pets. These conditions are key, though. Hermit crabs are fragile and not necessarily cut out for captivity. You’ll need to be patient and understanding of a hermit crab’s needs. If so, it will flourish and live a long, happy life.