The remarkable sand bubbler crab

October 5, 2017 • 2:30 pm

Should I have called this “You won’t believe this amazing crab?”. Or maybe “Samantha Bee throws shade on haters of bubbler crabs”? Regardless, you need to know about—and see—this remarkable animal. I knew nothing about it before I came upon this video, taken from BBC’s “Blue Planet” series.

Sand bubbler crabs comprise a variety of species in two genera, and live on Indo-Pacific beaches. As you see from the video below, they form sand into lovely spherical pellets after extracting the organic matter—the “meiofauna”. Sand bubblers forage only at low tide, and then retreat to their burrows.

Now what is “meiofauna”? The answer from

The term “Meiofauna“ is related to microscopically small benthic invertebrates that live in both marine and fresh water environments. Meiofauna is formally defined as a group of organisms by their size, larger than microfauna but smaller than macrofauna. In practice these are metazoan (some researchers include protozoan as well) animals that can pass unharmed through a 0.5 – 1 mm mesh but will be retained by a 30 μm mesh but the exact dimensions will vary from researcher to researcher. Nowadays the term meiofauna is used interchangeably with meiobenthos. Meiofauna is mainly found in and on soft sediments, but also on underwater algae and higher plants as well as on other hard substrates. The heterogeneity of meiofaunal habitats is so large and meiobenthic taxa so diverse.

Now watch and be impressed:

14 thoughts on “The remarkable sand bubbler crab

    1. You would think they would be. Soldier crabs, which also bubble sand, don’t get touched by birds. I’ve often wondered whether their defence is to be poisonous or distasteful. I can’t find a reference that says they are though.

  1. Very cool! I’m pretty sure I saw a large number of tiny, uniformly-sized sand balls like that on an Australian beach that I visited several years ago. I had no idea what they were!

  2. A sequel to the BBC Blue Planet series (Blue Planet II) is being released this year I think. It should be an excellent addition to the outstanding Planet Earth II.

    1. I just knew someone was going to do that when I first saw the OP. I was way too late to be the one though.

  3. I was interested in the weird fractal patterns of the balls. They looked like spider webs at first. Amazing critter.

  4. There are similar, or the same, crabs on the west coast of Costa Rica. Thousands of small sand pellets appear daily on the exposed sand & mud at low tide, arrayed around the burrows the crabs hide in.

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