As already mentioned beach crabs make mud balls by scraping off the surface sand and mud and, using their pincers, rolling them into little miniature mud-balls of such spherical precision and roundness as to be almost like ball bearings. These balls are then arranged in an ordered decorative necklace around their burrows.
But such planned behavior is by no means always the rule. Sometimes, as the above photos show, the crabs make these balls randomly, and leave them exactly where they were made, they not carting them off to their burrows for the precision alignment in concentric arrays.
In the above photos one can distinctly see the dark scrape marks made by their “claws”. One additional interesting feature that can be noted here is that unlike the balls placed around their burrows, which balls are marvels of engineering precision, these “balls” tend to be less perfect, in fact more irregular and oblong, almost cylindrical of aspect. It is almost as if the beast were in the grip of a creative impulse so undeniable that it continues carelessly making these balls even when fatigued, even when they are no longer needed for decorating and ornamenting its burrow.
Machilipatnam Beach. July 19, 2019. Andhra Pradesh.
