Hermit Crabs or Snail Lobsters?

“Hermit crab”? This thing looks precisely like the combination of a lobster and snail. Precisely.

Ah, hermit crabs. Where to begin with good ol’ hermit crabs, the perfect pre-dog childhood pet?

Other than their cute little eyes and fascination with fancy gastropod shells, the fact that hermit crabs were some of my first “personal” pets besides fish makes them one of my favorite crustaceans, and I could definitely see myself owning some again in the future. However, there was this heart-wrenching period of time in elementary school when hermit crabs continually came home with us from our family’s annual beach trip, stayed just long enough for us to get attached, and then died. Maybe they weren’t the best pre-dog pets after all.

My brother and I both got our first hermit crabs towards the beginning of elementary school. We named them Claw, Shelly and Current (who everyone kept calling Kermit, much to my annoyance). These little guys were “land hermit crabs,” orange terrestrial crustaceans that you can find in almost any beach tourist shop along at least the North and South Carolina coastlines.

Besides land and ocean crabs, there is one species of freshwater hermit crab, but you’re not likely to find it unless you live in Vanuatu, an island country between Fiji and Australia. It’s so sad that the river lobsters and snail lobsters will never meet – and yes, hermit crabs ought to be called snail “lobsters” as well, since they are more similar to lobsters than they are to other crabs. I believe this solely based on the fact that no other crab I know of has a head distinctly separate from its body.

Getting back to pets, our Claw/Shelly/Current trio lived long enough to meet two new crabs, Pinch and Tsunami, the following year, but Claw died soon after and was followed shortly by Shelly. Both crabs only lived for just over a year, and to this day I still don’t know how or why they died – in fact, the only crab with a pinpointable cause-of-death was my poor Current.

Shortly after Tsunami passed away (he had one of the shortest stays of all our crabs at only a few months), my brother and I found Current out of his shell and looking like a strange centaur creature with the upper half of a lobster and the lower half of a slug as he crawled around the enclosure in search of a new home.

We were so excited – finally! One of our crabs had lived long enough to choose a new shell! We innocently googled how long it would take for Current to pick a new home – and were horrified to learn that if he didn’t choose one within the hour, his body would get too dry and he would die. We spent the next 60 minutes glued to that crab cage, watching and hoping that Current would make it to a shell on time. Current didn’t seem to understand the gravity of the situation and took his own sweet time moseying around the tank. My brother and I eventually started putting shells right in front of him to hurry the process, but he was a very picky snail lobster and ignored every single one.

Finally, nearing the end of the hour, Current chose a new shell – and then immediately died the next day. So, while I can’t say for certain this is the case, I think that Current had been out of his shell for a while before we first saw him and passed the time limit sooner than we realized.

The third and final year of bringing hermit crabs home from the beach was the year we welcomed Storm and Sandy to the posse – and then Storm went and died that very day, earning himself the title of “snail lobster to break my heart the fastest.” I was so excited about bringing him back to NC, especially since he had a crudely drawn caricature of a certain electric yellow mouse on his shell, but he didn’t even live long enough for me to show him my trading cards. Sandy and Pinch lived peacefully in their tank for a couple more months before Pinch passed away, and Sandy ended up living for over two years, becoming the oldest crab we ever owned.

We thought Sandy was ancient when she passed away, but apparently hermit crabs are supposed to live up to 40 years in the wild. My excuse is that all our crabs came from tourist shops, and anything you get at a tourist shop tends to combust pretty quickly.

I’ve already explained why hermit crab isn’t necessarily correct, but “hermit” is a bit of a misnomer as well, since these guys often live in clusters of a hundred or so. My brother and I came across one such cluster of water-dwelling snail lobsters in some tide pools while on vacation in South Carolina again this year; we could hardly take a step without sending what at first appeared to be tiny, living seashells scuttling away in every direction.

Those tide pools proved to be very educational. In case you hadn’t heard this adorable fact about hermit crabs, some species will all line up biggest to smallest in a little snail lobster conga line whenever one of them finds a new shell. The crabs will pass the shell down the line until it fits someone, and then that crab may pass its old shell down the line to the smaller crab behind it, and so forth. Sounds like they have a happy, generous snail lobster society, right?

Unfortunately, this isn’t always the case. Some snail lobster herds, as I witnessed firsthand in June, don’t quite understand the concept of sharing.

The last day of our vacation, my brother and I went to walk through the tide pools and admire the hermit crabs one last time. Since I try to use my own pictures for The ArthroBlogger’s Instagram account as often as possible, I bent down to try and take a few snapshots of the little guys that I could put up when I published this post. I ended up filming what at first appeared to be two crabs chasing each other and stopped the video after a few seconds. However, I quickly resumed filming when we realized what was actually going on:

The two crabs were fighting over a shell, which was interesting enough until we realized that one of the brawling snail lobsters already had a shell and the other was fighting naked. We started rooting for the shell-less crab since he seemed to need a home the most, watching in anticipation as a third crab entered the fight. After a few moments, the shell-less crab warded off the other two just long enough to hop in the shell and dash away, much to our enthusiasm. But, the plot thickens:

When I looked back at the first video I had taken before we realized the crabs were fighting, I realized that the fought-over shell had actually belonged to the “shell-less” crab in the first place, but the second crab had climbed on top of the shell and tossed the first crab right out of it with an abrupt yank! Who knew snail lobsters could be so selfish?

This post has been a lot longer than most but it had a lot less science than usual, so I’m going to test the limits of your attention span and hit you with a speed round of wacky snail lobster facts before you go:

  • We all know plastic in the ocean is an issue, but it’s particularly detrimental to hermit crabs. When hermit crabs die, they release pheromones to alert nearby crabs that a new shell is available (morbid but true – snail lobsters aren’t snail lobsters without a snail-y shell). However, when crabs die in bottle caps and other plastic products, their death-stench draws in more crabs to the same fate.
  • While there are terrestrial species, all hermit crabs breathe using gills, so the land hermit crabs have to live in moist environments to stay wet even when they’re not in the water. That’s why you have to have a little pool of saltwater in your pet snail lobsters’ tank, so they can breathe properly.
  • In case it wasn’t obvious from the stories, hermit crabs don’t grow their own shells and instead live in the abandoned shells of whelks, moon snails, and other gastropods (I’m gonna call these fellas ocean snails)
  • Despite using an extra shell, hermit crabs also have exoskeletons like the rest of their arthropod brethren and need to shed this outer layer as they grow. Since they need to come out of the safety of their ocean snail shells to shed their exoskeletons, they often hide in the sand for the duration of the molting process.
  • Some hermit crabs will attach anemones to their shells to ward off predators. The anemone doesn’t mind this at all, as it gets to eat the leftovers from the hermit crab’s meals and gets carried around the ocean without having to move a muscle. Which is good, because I’m not entirely sure that anemones have any muscles to begin with.

Okay, that’s all, I release you from this blog now. Go! Be free!

And remember to properly dispose of your bottle caps, for the sake of young snail lobsters unexperienced in the realm of real estate!

2 Comments on “Hermit Crabs or Snail Lobsters?

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