Have you been to the beach and seen it covered in tiny little sand balls or seen perfectly circular pattern dotting the sand? Surely you’ve noticed them but what exactly are they and how did they get there?!?
These little sand ball patterns are thanks to the work of little crabs from the Dotillidae family. They are commonly called sand bubblers for the little bubbles or pellets of sand they make. The crabs live in burrows under the sand and wait patiently for the tide to go out so they can leave their burrow and feed.
Sand bubblers scoop up little bits of sand with their pincers, quickly filling their “mouthes” with bits of sand. There, they sift through the grains searching for bits of nutrients. Once they’ve sifted through the sand, they quickly discard it and carry on scooping up a new pile. Once discarded, the sand is in a perfect little sphere. As the crabs feed, they ofen work in a circular pattern so you will often see little spirals of sand balls at the beach. The tiny whole at the center of these patterns is the burrow entrance which the crabs will quickly jump into when they feel someone approaching. You need to be really quiet if you want to see them at work!
The sand bubblers need to work quick – as soon as the tide starts to rise again they will have to take shelter in their burrow. In fact, you can often tell how long the tide has been out based on how extensive the patterns are around the beach.
If you spend some time on Kantiang Beach, you’re sure to encounter these little guys scurrying across the sand. Spend some time at low-tide watching them do their work – it’s one of those fantastic things you have time to observe while relaxing on a tropical beach with no other distractions.