Hermit crabs are sometimes the subject of scientific testing, but not as much as other animals. So, many things remain unknown about hermit crabs, though some understanding of their cognitive function exists.
The extent of hermit crab memory span is unconfirmed. However, through scientific analysis and anecdotal evidence, we know they retain memories of important events and factors in their life.
Hermit crabs remember food because they never eat the same food twice in 24 hours and won’t consume anything that has made them unwell. Painful experiences will also be recalled and avoided.
Hermit crabs remember conspecifics that share a tank and their place in a social hierarchy. Your hermit crabs will recall a preferred shell, laying claim to it if it becomes vacant and familiar terrain.
Pet hermit crabs will also learn to remember you, albeit not by sight. Hermit crabs have an acute sense of smell and will associate your scent with pleasure if you’re patient and take the time to bond.
Do Hermit Crabs Have a Good Memory?
Hermit crabs are widely considered creatures of instinct.
Like many prey species, hermit crabs are driven by a primal urge to propagate their species by breeding in the wild. As scavengers, hermit crabs seek food daily, failing to store caches.
Despite these traits, hermit crabs can recall information. As we’ll discuss shortly, tests have shown that hermit crabs can recall conspecifics, painful experiences, familiar terrain, and more.
How long is a hermit crab’s memory? The hermit crab’s memory span has never been determined, but it’ll likely retain memories for a lifetime if it deems the information important enough.
What Do Hermit Crabs Remember?
Hermit crabs retain memories of things that matter most. They’re low on the food chain in the wild and quickly learn to keep themselves safe.
While stressful, life in captivity should be considerably safer for your hermit crabs. They won’t need to worry about predators, spoiled food, wild fluctuations in temperature, or anything else that would otherwise place their lives in danger.
All the same, hermit crabs ensure they remember any threats and sources of pleasure. While hermit crabs seem like creatures driven by instinct, they also hold onto memories that are considered important.
Pain
Numerous tests have been run on hermit crabs and their reaction to pain. These tests have shown that hermit crabs respond to painful experiences and retain memories to avoid repeating them.
Animal Behavior details a study where hermit crabs were shocked within their shells, monitoring their responses. Females responded faster than males, leaving their shells and declining to return when an alternative shell was available.
Interestingly, hermit crabs were likelier to return to a shell considered superior. This suggests they’ll consider pain worthy of tolerance if a sufficient reward is offered.
Food
Food is important to captive hermit crabs, often serving as their day’s highlight. The life and diet of pet hermit crabs vary from their wild counterparts, who rely on daily scavenging for snacks.
Some of this carries over into a captive hermit crab’s lifestyle. Your pets would reject food if they ate it in the last 24 hours, which proves that hermit crab memories last at least this long.
A study in The Biological Bulletin is of equal interest, which explains how hermit crabs avoid foods that previously made them unwell. This is essential for survival in the wild, where hermit crabs will encounter a variety of potentially edible toxins.
As food is a great motivator for hermit crabs, studies and anecdotal evidence suggest that memories surrounding nutrition are retained longest. Hermit crabs remember how to find food they enjoy.
Shells
Besides food, a safe and sustainable shell is the most important thing a wild hermit crab can source. Hermit crabs’ approach to shells is almost directly opposite to food. Rather than a novelty, they actively seek something familiar.
The Journal of Experimental Marine Biology and Ecology explains that hermit crabs will recall a previous shelter and look for a shell that resembles this. That means finding a shell with the same weight, opening, mobility, and protective qualities.
Some hermit crabs will look for a shell once occupied by a specific tankmate or associate from a colony in the wild. Your pets that share a tank will notice an appealing shell and remember who occupies it.
Hermit crabs will occasionally challenge a tankmate to access a favored shell. In the case of a more docile hermit crab, it’ll wait for the incumbent occupant to pass away before laying claim to the vessel.
Ecology and Evolution discuss how hermit crabs are drawn to the scent of a dead or dying conspecific. It would soon be approached if it sported the shell that has long been coveted.
Conspecifics
Hermit crabs are social animals. In the wild, they live in colonies of up to 100 or more, and it’s advisable to home hermit crabs in groups of four or more in captivity. These hermit crabs will quickly form and memorize a social hierarchy.
One hermit crab in a tank will rise to the alpha rank, while others also display dominant qualities. In most cases, these relationships will be respected. Ethology confirms that hermit crabs remember a dominant conspecific after 30 minutes of exposure.
If the interaction between the dominant and submissive hermit crabs wasn’t antagonistic, this memory isn’t a concern. If the hermit crabs struggled to co-exist, this would be reflected in their relationship. The hermit crabs will avoid each other, at least for a while.
Human Owners
Part of pet ownership revolves around bonding with hermit crabs. This isn’t simple with hermit crabs, as they’re not particularly cuddly and don’t actively enjoy being handled. Your hermit crabs will initially be wary of humans, but they’ll come to remember you.
Over time, you can gain the trust of hermit crabs so they’ll accept handling. This takes time and patience, as any human interaction can be frightening. Hermit crabs don’t understand our intentions, just that we’re large and loud.
Hermit crabs can’t tell humans apart by appearance, so how do hermit crabs remember you as an owner and differentiate you from others? The best way to gain the trust of hermit crabs is through food.
Try placing some jam on the tip of your finger. This snack’s sweet aroma and taste will enter the hermit crab’s memory alongside your unique scent.
Repeat this enough times, and the hermit crab will recall you as a source of pleasure rather than fear.
Territory
Hermit crabs are docile but territorial. They like to explore new terrain, often covering miles on a beach in the wild, and claiming parts of a tank for themselves when living in captivity. You’ll likely find each of your hermit crabs gravitates to a particular spot.
Familiarity is important to hermit crabs because they know where to find vital resources. According to Marine Behavior and Physiology, hermit crabs can get lost but always find their way home to the ocean.
A study in Biology Letters explains how hermit crabs memorize their way through a maze to receive a food reward at the exit. This suggests that hermit crabs remember key routes through familiar terrain.
While there’s some measure of comfort to be gained from familiarity for hermit crabs, they also enjoy unique layouts. When deep cleaning a hermit crab tank, don’t put everything exactly where it was. Place decor and toys in new locations to encourage interest.
Hermit crabs may be small, but don’t underestimate their intelligence or capacity for memory. They understand how to keep themselves safe and will call upon experience to live safely.
