From a distance, you see a grey mass marching up the shore like an army on a mission. Get close and you see their body clothed in grey armour, propped upon pink legs.
Get closer and you realise that they are small round crabs, each about the size of a marble – complete with their greenish eyes on red stalks! It is this habit of marching in large groups that gives these crabs their common name – Soldier Crabs Dotilla myctiroides.
My visit to the Devbagh Beach Resort had come to an end and I was waiting for the boat at the jetty to return to the mainland. It was low tide and a large expanse of sand was exposed when I witnessed the army of soldier crabs marching. I tried getting closer. I had taken but a few steps towards the nearest crab and suddenly the entire army disappeared! However, what I saw next was spectacular indeed – there were tiny balls of sand radiating from each tiny burrow!
I realised that my approach had to be a stealthy one if I had to get up-close to photograph these crabs. So, I sat down without a movement near the first burrow that I saw. In less than a minute I saw all of the army slowly surface again. I could clearly see the body, legs and eyes. Also noticeable were the really long pincers. Even as they came out, they started shovelling sand into their mouth rapidly with their pincers, leaving behind little sand pellets. (In this process, they feed on tiny creatures or the organic matter that gets washed ashore due to the action of the waves and tides.)
After watching them for a while, I decided to start shooting the crabs. I had to move to get the camera into position and this little movement was adequate for them to bury themselves into the sand quickly – they literally disappeared before I could even bat an eyelid!
When the tide was low, these crabs were busy feeding. With so many of them around, one should expect some conflict. Consequently, one can observe, between bouts of feeding, the crabs indulging in frequent fights with their neighbours. They used their long pincers to attack their neighbours.
At times, when two individuals were involved in a duel, a third would join the fray.
I had seen crabs move about before. However, when observing all this action, I realised that the Soldier Crabs moved differently – it took me some time to realise what it was. These little crabs not only could move sideways, that is so typical of crabs, but forwards too – and they run quite fast at that!
The sandy habitats of these crabs are subject to regular tidal action. During the low tides, the crabs go about feeding, fighting, etc. But, as the high tide comes in, the crabs burrow in the sand and trap a bubble of air that helps them tide over the period of submergence! As the tide recedes, they come out and get busy with their routine once again.