I’ve Got a Mantis Shrimp and I’m Not Afraid to Use It

(I hope you'll all forgive the last two days' worth of shameless self-promotion. I now return you to your regularly scheduled program...er, blog.)

On the day after Thanksgiving, our visiting relatives and we took a walk in the Zoo, where we crouched low and got alpacas to investigate us, saw small-clawed otters being adorable, and half froze in the chilly wind. We were all happy to get into the warmth of the Invertebrate House, where I tried not to pontificate too much about things like the water-vascular systems of echinoderms. As we looked into some of the smaller tanks, what should we see but a mantis shrimp! I had never seen it before, and a zoo employee informed us that it didn’t come out of its burrow very often.

In case you’re unfamiliar with them, mantis shrimp are not actually shrimp, although they do look kind of like big, extremely lengthened ones. They’re very territorial crustaceans that spend a lot of time tending to, and cleaning out, their burrows, and when other animals approach their territory they tend to lash out with a punch so violent that its force is equivalent to a .22-caliber bullet. They can even break aquarium glass, and we were told the mantis shrimp’s tank was specially reinforced.


It looked pretty mild-mannered to us, though, and very curious—but that could be its anatomy. Mantis shrimp have enormous compound eyes, each of which provides them with trinocular vision, and they can rotate these eyes independently of one another. When the mantis shrimp investigates a watching human (or their camera lens), its eyes rotate all over the place, and sometimes areas get darker or lighter; I don’t know what that’s about, but maybe there’s a pigment used for specific kinds of focusing? (Anyone who knows more about crustacean eyes than I do should jump in at any time.)


And the mantis shrimp does seem to like investigating people and things; the zoo employee (I don’t know her position) said that she’s sometimes able to lure the mantis shrimp out by putting her cell phone near the glass: it will come out to wiggle its eyes at it.

It was a fabulous sighting, not least because these crustaceans are so spectacularly colored around their eyes, chelipeds, and tail:


It also made me think about how mantis shrimp could be used in the commission of crimes: they could be weapons; they could break glass in robberies; they could serve as a distraction during a pickpocketing—the possibilities are endless.

Of course, you’d have to carry a bowl of seawater around with you, which might not help you look like an inconspicuous, innocent bystander, but I’m sure there’s a way around that. And once you figure that out, I bet a whole range of marine invertebrates could be handy criminal weapons/tools/accomplices! I’ll start making a list.

{A note: I do write all text and take all pictures. Please do not reproduce either without my permission.}