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Can Hermit Crabs Kill Each Other?

Can Hermit Crabs Kill Each Other?
The purpose of this blog is to share general information and is written to the author's best knowledge. It is not intended to be used in place of veterinary advice. For health concerns, please seek proper veterinary care. In addition, as an Amazon Associate I earn from qualifying purchases.

Unlike mainstream pets, not many people talk about how hermit crabs behave and interact with each other or their owners. Not only are these exotic animals a highly territorial and sociable bunch, but they also possess unique personalities that sometimes clash.

While aggression among hermit crabs is well-known to happen due to a variety of reasons such as playing or establishing a pecking order, owners often wonder how far their crabs can go; can hermit crabs kill each other?

In today’s article, we’re answering this question and several others as we dive deep into the fascinating world of hermit crabs.

Can Hermit Crabs Kill Each Other?

Two Hermit Crabs Fighting on a Beach

Unfortunately, the answer is yes. So, if you have a crabitat (a hermit crab habitat) with multiple members wandering about, you need to keep an eye on their behavior to avoid deadly incidents.

There are various ways that hermit crabs are known to use to kill one another, but they mainly resort to either:

  • Ripping the victims apart or out of their shells.
  • Digging up molting crabs and eating them alive — literally.

As first-rate scavengers, hermit crabs have no issues eating their own kind if need be.

Why do Hermit Crabs Attack Each Other?

If you have more than one hermit crab in your crabitat, chances are you’ve witnessed some of them engage in an array of aggressive behavior, or is it?

When dealing with hermit crabs, it’s important to be aware that what seems aggressive to us may not be the case for them.

It’s typical for hermit crabs -and many other animals for that matter- to climb over each other, push each other, or even snap their claws at each other as a form of playfulness or communication.

But what about the times when the flicking, pushing, and snapping get dangerous? This brings us to the conclusion that aggressive behavior in hermit crabs can either be normal or abnormal.

Below is a discussion of the reasons that may drive your hermit crabs into either route.

Normal Aggression

As we mentioned earlier, hermit crabs can act aggressively but not with an intention of harming each other. Here are a few examples of such behavior:

Establishing a Pecking Order

Due to their territorial nature, it’s a common practice among hermit crabs to demonstrate aggressive behaviors towards one another when they’re trying to establish a pecking order within the colony or habitat.

Form of such aggressive actions can include:

  • Antennae or feeler fights (more on this later)
  • Violent pushing out of the way
  • Violent flicking fellow out of the way.

These actions are usually not so serious that you should intervene. They’re merely the embodiment of animalistic/territorial instincts of the crabs and aren’t meant to hurt anyone.

In other words, they’re only a show of dominance.

However, when hermit crabs want to act in a way that’s harmful to fellow tank mates, you’ll see the difference. Aggressors will often try to pull their victims’ bodies out of their shells or attack their antennas, eyes, legs, claws, or abdomen.

If you witness actions that may hurt any of your hermit crabs, it’s critical that you separate the fighting parties until the attacker cools down. Tank aggression could be a sign of the beginning of molting or it could be a consequence of past episodes of getting bullied or picked on.

Tumbling

Strawberry Hermit Crab Climbing on Top of Another Hermit Crab

Tumbling is a common behavior among hermit crabs; one that’s easily mistaken as serious aggression by newbie owners. This is when hermit crabs climb on top of each other or push each other out of a favorite corner or spot in the tank.

Such actions are totally normal and won’t typically harm or injure your hermit crabs. It’s like when puppies or kittens playfully fight or push each other to get the closest spot to the mother.

It’s also comparable to adult dogs and cats rough-housing their young. The tumbling among hermit crabs is simply a natural way for these animals to learn and communicate.

Antennae Fencing

Antennae fighting is another normal aggressive behavior that hermit crabs like to engage in. Here, one crab goes up to another and the pair start to wiggle their feelers at each other or touch them together.

If you observe such fights, you’ll notice the crabs’ antennae moving and brushing against each other rapidly. This can go on for a few minutes until one of the crabs loses interest and the scene dies down.

This intriguing exchange can sometimes seem like the crabs are almost talking in code through antenna signals. We recommend you let your crabs do it -as long as no harming is involved- each other, to allow naturally develop their social skills within the colony.

Mating

At first glance, the mating ritual of hermit crabs often appears aggressive. But if you take the time to really observe the behavior of crabs during this period, you’ll notice that the male is simply protecting his female from other males by fending them off.

You’ll never see the male hermit crab trying to pull his female out of her shell. However, you may see him gently rocking her shell to entice her to come out from the shell so they can begin the mating process.

If the female resists such advances, the male will just follow her around and wait for her to change her mind. For females, the mating season starts after they molt. So, you’ll probably find male crabs lining up to pair with recently molted females.

Abnormal Aggression

The most common form of aggression among hermit crabs is shell fights, which are most likely to turn into abnormally aggressive actions that can result in death.

A shell fight happens when one crab tries to take over the shell of another crab and attempts to pull the victim out of it.

It starts with the aggressor making chirping noises while grabbing the victim crab’s shell and thrusting it back and forth. From there, things can escalate if the victim crab retreats inside the shell in dispute and tries to use their grasping claw for protection.

Otherwise, the victim crab may easily give in and just claim the shell that the aggressor abandoned.

How to Stop Hermit Crabs from Dangerous Fighting?

Closeup of a Hermit Crab Emerging From Its Shell

If you witness your hermit crabs engaging in shell fights, you should immediately intervene by removing the aggressor from the main tank and placing them in a separate container.

Then, provide the isolated crab with a variety of shells of different shapes, sizes, and weights. This gives the unhappy pet an ample chance to choose a suitable shell.

After the crab decides on a shell and gets used to it, you can return them to the main tank while keeping an eye on their behavior for a while to make sure that the transition went smoothly.

You may need to do this for the victim as well to prevent future fights.

Final Thoughts

So, can hermit crabs kill each other? In short, the answer is yes.

This mainly happens due to shell fights but can also result from the lack of food. Hermit crabs are known to kill one another by either ripping the victims apart or out of their shells, or by digging up molting crabs and eating them alive.