Sand bubbler crab (Scopimera) in Brunei

Have you ever wonder what those tiny sand marble-like things that cover the beach are? We know as little as them having something to do with the tiny crabs but why are they there and if the crabs made them, how?

I used to think these were granules of sand made into balls while the crab is making its home, excavating sand out of a hole. I was completely wrong! These sand patterns across the beach made out of tiny sand balls are the result after a sand bubbler crab has had its meal.

It eats tiny edible particles found in sand grains first filtering out the sand particles using its pincers and then its mouth parts. As it does so, the residue that comes out are made into a tiny ball of sand. It repetitively does this as it move across the beach floor and made sure there are clear passage to easily move in and out of its hole. Thus, forming a pattern of sand balls with lines leading to its hole.

Please view these documents for more detail:

Article: Sand bubbler crab Scopimera sp. Family Dotillidae by wildsingapore.com
Documentary Video: Fooled by Nature: Sand Bubbler Crabs by howstuffworks.com
Video: Sand Bubbler Crabs (Dotilla fenestrate) by stretta

Me wandering around taking pictures of random things. Though there was still bits of trash here and there, the beach looked much cleaner which pleased me a lot.


Sand bubbles that made patterns on the beach


Sand bubbles everywhere on the beach.


Where the lines meet, we can easily tell the locations of the sand bubbler crabs' homes.


I like this remote crab's hole as it tells you the direction its owner headed while taking a meal.


Sand bubbles and crab's foot prints


There's a nicely-camouflaged sand bubbler crab


Markings on the sand


Night was soon upon us when we left the beach and we'd always wanted to take a picture of this road with the trees arching towards each other on both sides.


A straight line across the sky amongst the clouds


My sister had wanted to show me a beautiful lake in one of the residential areas but unfortunately, it was probably too dark to see anything then. This is Jalan Muara road at night.