stridulation in hermit crabs

What Does Hermit Crab Chirping Mean?

While few animals are truly silent, hermit crabs are close. The noise made by hermit crabs is unique, a cross between a chirping cricket and a croaking frog. This is known as stridulation.

The reason for stridulation in hermit crabs is not fully understood. It is suggested that hermit crabs stridulate to ward off competition for shells or denote pain and irritation. Some hermit crabs also appear to verbalize when frightened or overstimulated.

If your hermit crab is being noisy, it is attempting to get the attention of somebody. This could be you or a fellow hermit crab. By observing the behavior of hermit crabs, you will gain a greater understanding.

Are Hermit Crabs Noisy Pets?

Hermit crabs are considered to be among the quietest pets that anybody can own. 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.

Hermit crab vocalizations sound like a chirp and a croak in one. This process, known as stridulation, varies in its frequency. It depends on the personas of the hermit crabs in question. Some hermit crabs rarely make a peep while others regularly attempt to communicate.

Even if you do have talkative hermit crabs, this is not enough to dub these animals, “noisy.” Stridulation is rarely loud enough to disturb somebody in the same room. The noise certainly will not travel between walls to annoy your neighbors or even roommates.

How Do Hermit Crabs Make Sounds?

Hermit crabs do not verbalize from a larynx. Rather, stridulation stems from rubbing body parts together inside the shell. This is 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 hermit crab owners anecdotally report hearing chirping when the walking legs are still. This suggests the hermit crabs use their four rearmost legs.

The penultimate pair of legs toward a hermit crab’s rear are likeliest to be used for stridulation. These small appendages are used to climb in and out of shells. As hermit crabs use their rear legs to clean the shell, they may also be used in stridulation.

why do hermit crabs chirp?

Do All Hermit Crabs Make Noises?

All hermit crabs are capable of stridulation, though this does not mean that all hermit crabs make noise. If your hermit crabs are silent, this suggests they are content and healthy.

Equally, some hermit crabs will start making noise seemingly out of nowhere. This will merit investigation. It may be nothing to concern yourself with. Your hermit crabs may just be growing more comfortable with each other and communicating.

Sudden noise can be a warning sign that something is amiss, though. You will need to assess. If your hermit crabs are acting out of the ordinary in any other way, consider why this may be.

Why Do Hermit Crabs Make a Chirping Noise?

What does it mean when hermit crabs chirp? This is a question that has baffled some of science’s brightest minds for years. Anecdotal evidence suggests that 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 are working in the realms of supposition. There are several possible explanations.

Deterring Rival Hermit Crabs

One form of hermit crab stridulation is vibrating. This activity is undertaken to warn rival hermit crabs away from a coveted shell. Along with potential mates, shells are the biggest cause of confrontation among hermit crabs.

Males, in particular, will often clash over shells. This is because male hermit crabs grow quickly, undertaking several molts in their earliest years. This leaves the crabs constantly seeking a bigger, better shell. This may be one currently sported by a tankmate.

Hermit crabs are not shy about challenging conspecifics for a new shelter. If a hermit crab wants a shell belonging to another, it will approach and start shell rapping. This is the act of clashing shells, trying to force the occupant out into the open to do battle.

As explained by Biology Letters, the owner of the shell will start to vibrate inside. This is a display of strength. The owner is trying to deter its opponent. The vibration essentially translates as, “listen to how strong I am. Are you sure you want to fight me?”

The challenging hermit crab will react accordingly. If confident – or desperate – enough, the aggressor will continue shell rapping. If not, it will walk away and seek an easier quarry. Hermit crabs rarely fight to wound and prefer to avoid a knock-down, drag-out battle.

Inter-Species Aggression

As discussed, hermit crabs will engage in conflict over shells. In most instances, this will be kept civil. There can be a thin line between negotiation and aggression, though. Some hermit crabs take their desire for a new shell too far.

As per Animal Behavior, particularly aggressive hermit crabs can evict rivals from a shell by force. This will typically be accompanied by increasingly loud chirping. Both hermit crabs are communicating their displeasure with the actions of the other.

Thankfully, most hermit crabs are capable of co-existing peacefully. This is especially likely if the crabs are of the same breed. Violence can arise, though. 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 alone. Start by doing so temporarily, letting the crab cool off then returning it. If the aggression continues, the hermit crab may need to live alone, or with one companion that it gets along with.

Wherever possible, keep hermit crabs together. As explained by Integrative Biology, the more time hermit crabs spend alone, the more antisocial they become. These animals live in groups of up to a hundred in the wild and prefer to live together in captivity.

Expressing Fear

Hermit crabs are believed to stridulate when afraid. A loud, squawking chirp is an expression of genuine fright. Something has happened to upset the hermit crab.

Take a look at what is unfolding in the aquarium. As discussed, hermit crabs do fight over shells. Not all hermit crabs are prepared to go through with this conflict. A smaller hermit crab may be frightened by the aggressive behavior of a larger rival, for example.

Also, ensure that there are no external threats. If you own other pets, such as cats, ensure they are not patrolling the hermit crab enclosure. These animals may start scratching and clawing at the walls. This will understandably frighten the occupants.

Cast your eye over the hygrometer too, ensuring the humidity of the habitat is appropriate. If hermit crabs experience dry gills, they struggle to breathe. This will be unnerving. Take a look in any pools of water too, ensuring a hermit crab is not struggling to escape a bath.

Agitation and Annoyance

The chirping of hermit crabs could also be described as an annoyed grunt. Hermit crabs chirp when disturbed and something displeases them. Common examples of when you may hear hermit crabs chirp include:

  • Disturbing sleeping hermit crabs through noise or spot cleaning
  • Moving hermit crabs out of their habitat for cleaning
  • Picking up a hermit crab that does not want to be handled
  • A tankmate climbing 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 have not yet consumed their fill
  • Playing loud music that distracts your hermit crabs from their activities

You may hear hermit crabs want to be left alone. Any kind of disturbance to the substrate above will be met with stridulation. The hermit crab is telling its tankmates to watch their step.

If your hermit crab starts chirping when you handle it, put it down ASAP. This handling may be unavoidable. You may need to pick up the hermit crab to move it ahead of cleaning the habitat. This is not the time to attempt to play with your crab though. Stridulation is a warning that it is agitated.

If you insist on prolonging the handling, you are likely to be pinched. Hermit crabs feel justified in this action. As far as they are concerned, you had your caution and you ignored it. They only attack in self-defense.

Requesting Assistance

Hermit crabs appear to stridulate to request help with something. Hermit crabs that live together will usually cooperate and help each other out. Alas, some hermit crabs are opportunistic. They see a struggling hermit crab as weak and make a play for its shell.

If you hear stridulation, look inside the tank. Is one of your hermit crabs trapped on its back? They can usually right themselves, but it may be struggling to do so. It may have fallen after hanging on the roof of the tank and be dazed.

Turn the hermit crab over and take a step back. If the stridulation stops and your hermit crab goes about its business, you have your answer. If the vocalizing continues, there must be another explanation.

Hermit crabs do not always stridulate by choice. Look for any warning signs that a hermit crab is trapped within a shell. If a shell is too tight, the legs will scratch and scrape constantly. This will become increasingly uncomfortable.

Under no circumstances try to pull the hermit crab from its shell. The hermit crab will resist and you’ll end up tugging off its limbs. Instead, guide it into a bath to moisten the shell. If necessary, use a paperclip to ease the crab out and into freedom.

what does it mean when hermit crabs chirp?

My Hermit Crab is Chirping for No Reason

Sometimes, hermit crabs appear to stridulate for no good reason. In these instances, they may simply be communicating with each other. There are still many mysteries surrounding hermit crab behavior. We are yet to unravel all the layers of these animals.

If your hermit crabs frequently stridulate at low volume, you can usually leave them to it. If the noise continues for longer than a few minutes, it merits investigation. Most hermit crabs do not stridulate for more than a few seconds at a time.

If the reason for stridulation is not obvious, try to think outside the box. Your hermit crabs are trying to communicate something. If the stridulation becomes louder and more desperate, they are keen to be paid attention.

If your hermit crabs are not fighting or trapped, consider these possible explanations for the noises coming from the tank:

  • Humidity is low and the hermit crabs are growing uncomfortable
  • The tank needs a spot clean and the hermit crabs feel unsanitary
  • They are hungry. Have they been fed? Did they eat what was provided?
  • You have left a light on when the hermit crabs were expecting darkness

Learning why hermit crabs stridulate for no reason can feel like a trial-and-error process. If you spend enough time with your pets, you will learn their foibles. This will help you respond to stridulation accordingly.

Some will claim that hermit crabs chirping is never a good sign. This is not necessarily the case. Hermit crabs chirp for a range of potential reasons. All the same, it never hurts to look at what is unfolding in an aquarium. One or more of your hermit crabs could be in distress.