Hermit crabs are a fascinating type of crustacean that have adapted an ingenious way of protecting their vulnerable abdomens – by sheltering inside empty seashells. We’re accustomed to spotting hermit crabs scuttling along the seashore or tide pools, transporting their portable homes on their backs. But have you ever been curious about how these quirky creatures appear when out of those borrowed shells?
In this article we’ll take a peek at the anatomy of a hermit crab in its natural state without a seashell casing. We’ll examine how vital shells are for their continued existence the process they undertake to upgrade their shells, and what transpires when they’re unable to acquire an appropriate shell.
Why Hermit Crabs Require Shells
Hermit crabs aren’t born with the capacity to produce their own defensive covering or shell Their bodies possess a soft, coiled abdomen that is susceptible to predators. They lack the durable exterior skeleton that other crabs have So to endure, they adapted the clever tactic of locating empty shells deserted by aquatic snails and slipping inside for protection and shelter.
Seashells are literally a matter of life or demise for hermit crabs. They rely on shells to guard their abdomens from predators, shield them from rough ocean currents, retain moisture in their gills for respiration, and prevent damage during reproduction. Without a seashell, the delicate underbelly of a hermit crab is uncovered, making it extremely vulnerable.
The Anatomy of a Shell-Less Hermit Crab
So what does a hermit crab’s body resemble when out of that acquired shell? The most noticeable characteristic is its curved, spiraled abdomen. Since hermit crabs can’t fully retract their abdomens into their bodies like other crustaceans, this soft portion requires additional protection.
The remainder of the body consists of:
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Legs and claws: Hermit crabs have 5 pairs of legs for ambulating and 2 large claws for seizing food and self-defense.
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Eyes: Their eyestalks contain compound eyes that assist in detecting light and movement.
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Antennae: The long antennae aid the crab in picking up chemical signals from its habitat.
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Mouth: The crab’s mouth possesses appendages specialized for tearing apart food.
Without its trusted seashell, the hermit crab’s body is twisted in a spiral form to safeguard the abdomen. The legs, claws, eyes, antennae, and mouthparts are completely exposed.
The Shell Switching Process
As hermit crabs mature, they require larger shells periodically to accommodate their increased size. Hermit crabs will gather together and line up to inspect empty shells. When a crab finds a suitable fresh home, others will approach and try on the shell for proportions.
Shell switching initiates with a scuffle as crabs fight over the optimal shell. The winner gets to occupy the new shell while other crabs wait for another vacant shell to hopefully come along. During the procedure of switching homes, the hermit crab is completely defenseless without any shell shielding its body. It has to work swiftly to transfer itself from one shell to the next so its abdomen stays protected.
Dangers of Being Shell-Less
Sometimes hermit crabs struggle to locate a properly fitting shell as they grow. This leaves them exposed and endangered in several ways:
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Predators: Being shell-less means the crab’s abdomen is prone to predators attacking it. Fish, birds, and other crabs perceive the exposed crab as an easy snack.
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Weather: Without the armor of a shell, waves, tides, and currents can toss the hermit crab around and injure its delicate body.
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Dehydration: Staying moist is imperative for gill function and oxygenation. A shell assists the crab in retaining water in its body.
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Reproduction: Mating is problematic and risky for hermit crabs without shells to safeguard their vulnerable undersides.
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Fights: Other hermit crabs will capitalize on a shell-less crab and be more likely to initiate fights with the unprotected animal.
Hermit Crab Shell Scarcity
Pollution is creating a severe dilemma for hermit crabs globally – a deficiency of intact seashells for them to utilize as habitats. Many beaches are littered with plastic that hermit crabs mistakenly try to use rather than shells. But plastic traps heat, causing them to overheat, and lacks the structure to appropriately protect them.
Researchers have been alarmed to uncover that up to 90% of hermit crabs in certain areas are now employing manmade objects and trash as makeshift shells due to the extreme lack of natural seashells. As rubbish like plastic straws and styrofoam replaces shells, it jeopardizes hermit crab populations. Without our assistance to clean up beaches and conserve their shell supply, these fascinating creatures face an uncertain future.
The next time you’re fortunate enough to glimpse a minuscule hermit crab scuttling by with its shell-house in tow, take a moment to appreciate the ingenious way it adapted to uncover shelter. And consider aiding in preserving the shells it depends on so critically for its endurance!
Below we expand a bit on these causes.
Land Hermit Crabs endure a great amount of stress before reaching the pet store. The harvesting and shipping of hermit crabs is a very inhumane process and the crabs suffer because of it. They then arrive in pet stores, who in most cases, don’t know how to properly care for them. They arrived stressed out, dehydrated and hungry. Then you purchase them and take them home. Now severely physically damaged the hermit crab will often leave its shell to die.
If there is not a variety of appropriate styles and sizes of extra changing shells in the crabitat for the hermit crab to choose from, there may also be shell fights. This is normally dangerous for the hermit crabs within the crabitat due to the fact that hermit crabs would rather let themselves be pulled apart as opposed to giving up their protective home. Many times this leads to a hermit crab being seriously injured or even killed by the aggressive hermit crab in search of a comfortable shell. There are times too when a hermit crab is shell shopping and may of let go of his original shell to try another on and has his shell taken by another tank mate. This forces the hermit crab to find another shell, if a suitable one isn’t available it is left homeless.
Something may have got into his shell and is irritating his soft abdomen. One can rinse the shell out with dechlorinated water, but many times if something is lodged within the shell this doesn’t help much. Boiling the shell in dechlorinated water and giving it a good shake will many times dislodge anything that may be within it. There maybe pests or a fungus within the shell that is irritating his abdomen and will cause him to leave the shell.
If the hermit crab is too warm, to try to cool off a hermit crab will leave their shells. To prevent over heating it is very important to monitor the substrate temperature as well as the air temperature. The temperature at the warm end of the crabitat should be approximately 80-82F. At 85F or higher this is nearing too warm for most hermit crabs to be comfortable (some species do enjoy higher temperatures). The temperature at the cool end of the crabitat should be approximately 72-75F. Hermit crabs are ectothermic creatures and must have the variance of temperatures to self regulate.
If the humidity level is too low in the crabitat hermit crabs feel as though they are suffocating. In hopes of relieving the discomfort they are experiencing they leave their shells. If they had been subjected to a too low humidity, too many times it has already caused irreversible gill damage. For a more accurate humidity percentage reading level, the humidity gauge should be located close to substrate in the middle of the tank away from water sources that can affect the gauges reading. The safe range is 70-80% relative humidity. Cheap analog gauges from pet stores are rarely accurate.
Please calibrate your humidity gauge to ensure how accurately it is reading:Calibration
A hermit crab will also leave their shell due to a too high of a humidity percentage. A high humidity level makes it difficult for the hermit crab to breath due to the ‘thicknesses’ of the humidity. If subjected to a too high humidity level, this can promote a gill infection that may cause irreversible damage. Maintaining humidity levels of 90% and higher is discouraged.
And even though it is rare, he maybe in premolt or be molting. Pre molt symptoms
What’s Inside a Hermit Crab Shell?
FAQ
Can a crab live without a shell?
Only small hermit crabs are able to live without remodelled shells. In an experimental setting, most big hermit crabs that are transferred to a size-matched normal shell die. Even if they were able to survive, hollowing out a shell takes precious energy, making it undesirable to any hermit crab.
What does a ghost crab look like?
Young ghost crabs are much darker than adults, with shells colored a mottled gray and brown. These crabs have four pairs of walking legs and one pair of white claws, and their large, club-shaped eyestalks can rotate 360 degrees.
What is a crab without a shell called?
Hermit crabs are small crustaceans that lack a shell and must “borrow” one from another animal.
What happens when a crab loses its shell?
Molting: How Crabs Grow
Because they have a hard outer shell (the exoskeleton) that does not grow, they must shed their shells, a process called molting. Just as we outgrow our clothing, crabs outgrow their shells.