Hermit crabs are different from regular crabs – they’re closer to insects in terms of the way they move.
While most true crabs have stiff joints that encourage side-to-side movements, hermit crabs crawl forward and backward using their six pereopods (legs).
Hermit crabs crawl like insects rather than scuttle sideways; if you see a hermit crab dragging its stomach on the floor, its shell may be too big.
How Do Hermit Crabs Move?
According to the Journal of Experimental Biology, hermit crabs move similarly to insects. They have six pereopods (legs) which help them crawl around.
Hermit crabs alternate between their second and third pereopods to propel themselves forward. The chelipeds (legs with claws) are primarily used for support, and this support becomes especially important for supporting the shell.
Even though the hermit crab has an irregular body, its walking pattern helps it to remain stable and balanced. For example, its left legs can stretch out longer than its right legs to compensate for its shell being slightly on the right side of its body.
Do Hermit Crabs Walk Sideways?
No, hermit crabs don’t walk sideways like true crabs.
Most crabs have joints in their legs that bend sideways instead of forwards, making it much more natural to scuttle sideways than walk forwards.
Hermit crabs don’t have this side-bending joint so they can crawl forward like insects and lobsters.
Indeed, technically hermit crabs aren’t crabs because they don’t have the same gait or grow their shells.
According to National Geographic, Hermit crabs can grow a hard exoskeleton for the front of their body, but they need a shell to protect the rest of their body.
Instead of growing their shell, hermit crabs salvage the discarded shells of other sea animals or seek out crabs that have already died and re-purpose their shells.
Can Hermit Crabs Walk Backward?
The hermit crab’s legs can facilitate forward and backward motion. Most crabs can only shuffle backward, but hermit crabs can take steps backward due to their anatomy and unique gait.
Will you see your hermit crab walking backward regularly? Probably not.
Some hermit crabs combine walking forwards with walking backward when placed in a new enclosure. Also, some hermit crabs walk backward while trying out a new shell.
Although it might look strange, it’s not usually a problem if your hermit crab is walking backward.
In truth, all crabs can ‘move’ in all directions, but most crabs prefer side-to-side movement, whereas hermit crabs prefer forward-and-backward movement due to how their bodies are built.
How Often Do Hermit Crabs Move?
Hermit crabs don’t move around much. They’re a prey species, so they recoil at the first sign of danger. Indeed, this is how they earned their status as a hermit. Hermit crabs are friendly with each other and prefer to live in clusters rather than lead solitary lives.
Hermit crabs don’t travel very far in terms of distance. One study from Science Direct found that wild hermit crabs moved about 26 meters in 24 hours (using a timelapse camera).
Over the 24 hours, there was a mixture of continuous travel and rest periods (lasting between 2 and 6 hours). So, if you catch your hermit crab at the right time, you can witness them moving around.
Hermit crabs aren’t particularly active pets; the joy comes from observing their unique patterns of behavior rather than from spending lots of interactive time with them.
What Affects a Hermit Crab’s Movements?
In the wild, the hermit crab’s movements are affected by the tide and changes in light.
Hermit crabs are also startled by loud noises and sudden movements, making them less likely to move around in a noisy home.
Like all animals, hermit crabs have unique personalities, so their willingness to move about can vary.
It’s important to say that when a hermit crab is molting, it won’t move for about four weeks. This is because it needs to grow a new exoskeleton. Unfortunately, some pet owners mistake this period of stillness for death.
Molting happens approximately every 12-18 months, so your hermit crab will go through periods of stillness approximately every year and a half. If you can support your hermit crab in this continuous process of molting and renewing, it could live for up to 40 years.
How Fast Do Hermit Crabs Move?
Hermit crabs aren’t particularly fast-moving. Instead of crawling away in the face of danger, they’ll usually recoil back into their shell.
According to the above study, the hermit crabs tended to stay close to ‘home,’ limiting themselves to a small radius in the ocean. They’re not the type of creatures to travel miles and miles.
Essentially, hermit crabs don’t travel far or fast.
Do Hermit Crabs Shuffle Around?
If you see your hermit crab shuffling around, it could be because its shell is too big and heavy.
A hermit crab can lift its abdomen off the floor when it walks. However, if its shell is too big, its legs may not be able to support the weight, causing it to drag its tummy on the ground.
If your hermit crab can’t lift its abdomen off the ground, you should try offering it different shells that are slightly smaller or lighter than its current shell.
How Often Do Hermit Crabs Need a New Shell?
One of the reasons a hermit crab moves around is to replace its shell.
According to Springer, the hermit crab’s ability to plan for and execute and its change-of-shell shows its sophisticated cognitive and perceptual abilities.
For example, did you know that when a new shell is found in the wild, a group of hermit crabs will line up beside it and each try it on for size? Then, whichever hermit crab takes, it’ll pass the shell down to the next hermit crab so that everyone benefits from the exchange.
This is an amazing example of teamwork in the natural world.
Hermit crabs sometimes fight each other for their shells, leaving both the victor and the loser injured. Hermit crabs can also sensitively detect when a shell will become available (e.g., when another hermit crab is near the end of its life), and they lay in wait until the shell becomes available.
Given the importance that shells hold in a hermit crab’s life, you’ll need to provide replacement shells after your hermit crab has finished molting. It’s best to provide a variety of shells so that your hermit crab can try them on for size.