Hermit crabs live in large colonies in the wild and prefer to replicate this in captivity over living alone. This means that hermit crabs communicate among themselves.
Hermit crabs verbalize by chirping (stridulation). Loud, intense chirping suggests a hermit crab is upset. They also communicate through their antennae, which pick up chemical cues and help hermit crabs recognize each other as individuals.
Exchanging shells and play fighting could also be seen as forms of hermit crab communication. This will involve antennae wrestling, attempts to push each other over, and rapping on the shell. Some hermit crabs welcome interactions, while others hide to avoid them.
Most hermit crabs in captivity will co-exist, interacting with each other when desired and hiding when seeking privacy. It’s easy to determine when hermit crabs are content and must be separated.
Are Hermit Crabs Social?
Hermit crabs are used to living with each other. In the wild, hermit crabs are parts of colonies of over a hundred. So, a tank should host at least four hermit crabs to help them adjust to captivity.
As with all animals, pet hermit crabs can still fight. According to Behavioral Ecology and Sociobiology, some hermit crabs communicate more than others.
If you keep hermit crabs of the same breed, they’re likelier to be social.
Regardless of the different species of hermit crabs, they grow bored if left alone for too long. This is dangerous, as boredom leads to stress, unwanted behaviors, and ill health.
Do Hermit Crabs Like to Socialize with Humans?
While you can interact with hermit crabs, you must earn their trust first.
You’ll likely be pinched if you immediately attempt to handle hermit crabs upon adoption. This isn’t an act of aggression but one of self-defense and fear.
Once your hermit crabs have adapted to life in captivity, they’re likelier to respond well to human interaction. Your presence may even be considered a pleasure source, but it’s advisable only to handle hermit crabs when necessary.
Do Hermit Crabs Have Personalities?
All animals have a personality, and all hermit crabs are unique. A handful of traits are associated with all hermit crabs, but some will showcase disparate qualities.
The archetypical personality qualities of a hermit crab are:
- Shyness, especially when faced with an unfamiliar environment. Expect your hermit crabs to hide a lot, especially when you first bring them home.
- Curiosity. Once adaptation is complete, hermit crabs like to explore their surroundings, especially climbing the walls of a tank.
- Food-driven. Most hermit crabs will show interest in food, especially if it’s something they haven’t eaten recently.
- Docility. It’s rare for hermit crabs to be aggressive to each other or human owners, although they may pinch when afraid.
When pairing hermit crabs in a single tank, assess compatibility. You may find that one occupant is more dominant and aggressive than others, or another is particularly shy and nervous.
If this is the case, do what you can to make all the hermit crabs in your care comfortable.
How Do Hermit Crabs Interact with Each Other?
Hermit crab interaction is primarily conducted through body language and physical contact.
Hermit crabs are vocal, often chirping while active at night, but watching your hermit crabs reveals more about their dynamics than listening.
Do Hermit Crabs Talk to Each Other?
Hermit crabs are vocal but lack a distinctive verbal tic akin to a cat’s meow or a dog’s. The sound that comes from a hermit crab tank will be a series of chirps, similar to a field of crickets.
To create noise, hermit crabs rub their chelipeds against each other or their shell. This is known as stridulation. Sometimes, this is simply a conversation among hermit crabs. For example, you may hear chirping when food is served.
A hermit crab is likely distressed or frightened if the chirping is loud and shrill. The sound could be a cry for help if a hermit crab is trapped on its back, or it could be a noise of protest if one hermit crab climbs over another.
If you hear loud chirping, look into the tank and ensure two hermit crabs aren’t in conflict.
Body Language
The body language of hermit crabs is more revealing than any verbalization.
Learning what different postures and behaviors mean when two hermit crabs interact is essential. This way, you can be sure that your pet hermit crabs feel safe in their environment.
Hermit crabs use their antennae to interact with each other.
Current Biology explains how a hermit crab antenna can detect chemical cues. This enables hermit crabs to determine whether another animal is a friend or foe and the condition of a shell.
These chemical cues determine how hermit crabs respond.
As per Social Recognition in Invertebrates, hermit crabs remember conspecifics individually. If they’ve had a negative interaction in the past, one or both will hide or show aggression.
Play Fighting
Hermit crabs may indulge in playfighting to pass the time. This is often harmless, but you must recognize the difference between hermit crabs playing and bullying one another.
Hermit crabs are docile and friendly, but light-hearted conflict can turn aggressive, especially when battling for territory. Wild hermit crabs will also fight over the right to mate with a female, but as captive hermit crabs rarely breed, this is of little concern.
Play fighting among hermit crabs takes two major forms. If chelipeds remain unused and neither hermit crab hides nor walks away, leave the animals to play. If one starts pinching with claws, especially aiming for the eye sockets, separate them.
Feeler Fights
Hermit crabs often interlock antennae to gain new information and communicate. They also sometimes indulge in ‘feeler fights.’ Think of this as hermit crabs arm wrestling. Sometimes it’s a quest to assert dominance, but it’s often just for fun.
If neither hermit crab is walking away or chirping loudly, leave them to indulge in their game. Just be aware that, as per Animal Behavior, hermit crabs can experience pain through the antennae.
Tests of Strength
Hermit crabs sometimes conduct tests of strength by attempting to push each other. Sometimes this is just a game, but it can also be an attempt to establish dominance.
If it’s exclusively a game, the two hermit crabs will take turns to push and to be pushed. Equally, if a hermit crab is flipped over, a friendly conspecific will assist it back to its feet.
If one hermit crab hides in its shell despite a barrage of pushing and starts to chirp with increasing volume and desperation, it no longer considers this a game.
Shell Trading
It’s rare for two hermit crabs to share a shell, especially in captivity. This means that shells become a key commodity when establishing a social hierarchy in a shared enclosure.
If a hermit crab decides to change its shell, it creates a ‘vacancy chain’ in which all hermit crabs line up according to size. Each hermit crab will try on the newly vacated shell until each colony member has a new shell or decides they’re happy with their existing vessel.
The most common explanation for a change of shell is molting. After a molt, a hermit crab will have grown and likely be too big for its previous shell. Hermit crabs also change shells when an existing vessel becomes damaged.
Some dominant hermit crabs covet a shell worn by a conspecific. The hermit crab will challenge the incumbent for the right to the shell. This may take the form of a feeler fight, a test of strength, or even aggressive combat or dragging the hermit crab from the shell.
A challenge for shell trading begins with rapping on the shell. If the shell owner isn’t interested in trading, it’ll hide. This can lead to intense rapping until the aggressor eventually grows weary and moves on.
Proceedings of the Royal Society of London explain how battling over a shell can have long-term repercussions. If a hermit crab is forced to give up a shell against its will, it’ll consider the rival an enemy to be avoided in the future.
Hermit crabs enjoy living with their own kind and mostly get along. Be vigilant about understanding hermit crab behavior, and ensure everyone is happy and comfortable with each other.
