True Facts : The Sand Bubbler Crab

It is low tide, and Henry, a sand bubbler crab in the family Dotylidae, is digging out his hidey hole. So is little Emma, and she's very good at it. These burrows will provide protection. David, on the other hand, is a total idiot. He's just playing scratchy-scratchy in the sand. You're probably going to die, David. Let me ask you a question. Do you like balls? If your answer was yes, well then this is number one good time crab for you. Because sand bubbler crabs make balls. But this isn't some fraternity brother two-finger roll flicking a booger on the carpet. And they won't be fired out of a tiny cannon either. Instead, these sand bubbler crabs are eating the sand. If you have eaten sand before, you might be thinking, why the f*** are you eating sand? It turns out Henry's mouthparts have evolved into a kind of tiny washing machine. The sand he picks up is mixed with water stored in his gill chambers, and tiny bits of organic matter come loose from the grains. Those are ingested and the sand is spit out. It's kind of like if when you were hungry, your instinct was to eat the dirty dishes in a dishwasher to get whatever crap was stuck on them. That is how the sand bubbler crab do. But also, if you look closely, there are other tasty morsels living in the low-tide sand. We know this because scientists have used their sciences to look at them. Like the ribbon worm Nemertia, who was kidnapped by aliens and looked at naked under a bright light. Or the larva of a peanut worm, which you know pops in your mouth a bit. Or like these little hydromedusae, where one's all like, boots and socks and boots and socks, and the other one's all like, bow bow bow bow. Oh, no plans tonight, just staying in watching Fleabag. Oh, we're going to the club. One second. All right, I'm ready. And of course, the tardigrade, or water bear, with its cute little feet. When you build a sand castle, these are your subjects. For most of them, it will be the highest up they will ever be. The chance to join the one foot high club, if you know what I mean. I mean, ****. But these creatures are very, very small, and the sand bubbler crab must eat for up to five hours to get a full meal. In order to stay safe, Henry, pictured here with a coin so you get a sense of how rich he is, builds feeding trenches out in radial lines from his burrow. Eating sand from one side and moving the balls behind him ensures a clear escape path in case the plovers or sandpipers come. Told you, David. As they move outwards on the exposed beaches, they use specialized adaptations to get oxygen and water. On their upper thighs, they have oval gas windows through which they can breathe. Little tufts of hair like setae on their feet or abdomen can pull water right out of the sand as they walk. As the day wears on, competition for burrows can get fierce. Oh dang, he threw him! That dude's got moves like Yoda in the second worst Star Wars movie. But seriously, it can get a little crowded. It is like the opposite of the game of golf, where the goal is to get as many balls outside the holes as possible, and it can get hard to tell what balls have been inside whose mouth already. As the rising tide approaches, the sand bubbler's work is almost done. Its final job of the day is to create a dome-like structure. This will give it a little bubble of air as it burrows deep into the sand and waits for the next low tide to come. And dreams of balls. Yo, check this out. I'm little, I'm little, I'm big.