While few animals are truly silent, hermit crabs are close. The noise made by hermit crabs is called stridulation, which is a cross between a chirping cricket and a croaking frog.
It’s suggested that hermit crabs stridulate to ward off competition for shells or denote pain and irritation. Some hermit crabs also verbalize when afraid or overstimulated.
If a hermit crab is noisy, it’s attempting to get the attention of another hermit crab.
Are Hermit Crabs Noisy Pets?
Hermit crabs are considered to be among the quietest pets.
Hermit crabs aren’t completely silent, though. Their legs clack when climbing the walls of their habitat, and shells often clash. Also, hermit crabs communicate with each other.
Hermit crab vocalizations sound like a chirp and a croak in one. This process, known as stridulation, varies in frequency. Some hermit crabs rarely make a sound, while others regularly communicate.
Even if you have talkative hermit crabs, you can’t describe them as noisy. Stridulation is rarely loud enough to disturb somebody in the same room, let alone a neighbor.
How Do Hermit Crabs Make Sounds?
Hermit crabs don’t verbalize from a larynx. Rather, stridulation occurs due to rubbing body parts inside the shell, similar to crickets rubbing their wings together. This, presumably, is why the sound is comparable to a cricket’s chirp.
The most popular theory is that hermit crabs knock their legs together or scrape a leg against their shell. Many owners anecdotally report hearing chirping when the walking legs are still, suggesting that hermit crabs use their four rearmost legs.
The penultimate pair of legs toward a hermit crab’s rear is most likely to be used for stridulation. These small appendages are used to climb in and out of their shells. As hermit crabs use their rear legs to clean their shells, they may also be used for stridulation.
Do All Hermit Crabs Make Noises?
All hermit crabs are capable of stridulation, though this doesn’t mean that all hermit crabs make noise. If hermit crabs are silent, this suggests they’re content and healthy.
Equally, some hermit crabs will start making noise for seemingly no reason. Your hermit crabs may be more comfortable communicating with each other.
However, sudden noise can be a warning sign that something is amiss.
Why Do Hermit Crabs Make a Chirping Noise?
Reasons why hermit crabs chirp includes:
- Fear
- Deterrence
- Aggression
- Stimulation
- Discomfort
As you can see, this is a broad church of definitions. As the question, “why do hermit crabs chirp?” has no definitive answer, we’re working in the realms of supposition. There are several possible explanations:
Deterring Rival Hermit Crabs
One form of hermit crab stridulation is vibrating, which is undertaken to warn rival hermit crabs away from a coveted shell. Along with potential mates, shells are the main source of confrontation.
Males, in particular, will often clash over shells because they grow quickly, completing several molts in their earliest years. This leaves hermit crabs constantly seeking a bigger, better shell.
Hermit crabs aren’t shy about challenging conspecifics for a new shell. If a hermit crab wants a shell that belongs to another hermit crab, it’ll approach and start shell rapping. This is the act of clashing shells, trying to force the occupant into the open to do battle.
As explained by Biology Letters, the owner of the shell will start to vibrate inside, which is a display of strength. The owner of the shell is trying to deter its opponent.
The challenging hermit crab will react accordingly. The aggressor will continue shell rapping if confident – or desperate – enough. If not, it’ll walk away and seek an easier opponent.
Inter-Species Aggression
As discussed, hermit crabs engage in conflict over shells. In most instances, this will be civil, but there can be a thin line between negotiation and aggression.
As per Animal Behavior, aggressive hermit crabs can evict rivals from a shell by force, typically accompanied by increasingly loud chirping. Both hermit crabs are communicating their displeasure with the actions of the other.
Most hermit crabs co-exist peacefully, especially hermit crabs of the same species. However, aggression can occur, as every hermit crab is unique, and some are more antagonistic than others.
If you have one hermit crab that seems overly aggressive, consider rehousing it for a while. Start by temporarily letting the hermit crab calm down before returning it. If the aggression continues, the hermit crab may need to live alone or with one compatible companion.
Expressing Fear
Hermit crabs are believed to stridulate when afraid. A loud, squawking chirp is an expression of fright.
Hermit crabs can fight over shells, but not all are prepared to fight. For example, a smaller hermit crab may be frightened by the aggressive behavior of a larger rival.
Also, ensure that there are no external threats. If you own other pets, such as cats or dogs, ensure they’re not patrolling the hermit crab enclosure because this can frighten the occupants.
Check the hygrometer to ensure the humidity level is appropriate. If hermit crabs experience dry gills, they’ll struggle to breathe and eventually die.
Agitation and Annoyance
Hermit crabs chirp when disturbed or something displeases them. Common examples of when you may hear hermit crabs chirp include:
- Disturbing sleeping hermit crabs.
- Moving hermit crabs from their habitat.
- Picking up a hermit crab that doesn’t want to be handled.
- A tankmate climbs over the top of a prone hermit crab.
- Turning on bright lights during a scheduled period of darkness.
- Taking away uneaten food if the hermit crabs are still eating.
You may hear chirping when hermit crabs want to be left alone.
Requesting Assistance
Hermit crabs that live together will usually cooperate and assist each other. Alas, some hermit crabs are opportunistic, seeing a struggling hermit crab as weak and making a play for its shell.
Is one of the hermit crabs trapped on its back? Hermit crabs can usually flip themselves over, but they may struggle. If so, it’ll need your assistance.
Hermit crabs don’t always stridulate by choice. Look for warning signs that a hermit crab is trapped within a shell. The legs will scratch and scrape constantly if a shell is too tight.
Under no circumstances should you pull the hermit crab from its shell, as it’ll resist, so you’ll end up tugging off its limbs. Instead, guide it into a water bowl to submerge and moisten the shell interior.
