The big rocks at Changi are teeming with 'metopos' or the Purple climbing crab (Metopograpsus sp.).
As their name suggests, they are excellent climbers and many have bright purple pincers.
Here's a handsome specimen. It has a huge barnacle between its eyes! And very hairy legs!
On the rocks today, I saw many Purple climbing crabs, I stopped counting after 20. They came in all sizes including really tiny ones with a body width hardly more than 1cm. There were several with only one pincer. Oh dear.
The big rocks are riddled with holes of various sizes. And each hole shelters at least one crab! The rocks are Metopo condos!
These crabs are shy and quick to hide. So if you come by in the daytime, all you might see is a seemingly barren rock. Even in the dark, these flattened crabs are well camouflaged against the rock so you need to look carefully and quietly to avoid frightening them.
Thanks to Siva for making me look for them, I actually saw the Meto metropolis today!