I always wondered why they were there. Why do they roll in with the waves just to burrow back down into the sand? Why don’t they just stay underground? Do they have to come up to eat? We used to catch them and feel them scamper around in our hands. I used to be afraid they would burrow through my skin. We would collect them in our 10 gallon plastic bucket and try to observe them undisturbed by the tumult of the tide, though perhaps more for sport than any investigative endeavors.
Interestingly at night, they don’t seem as eager to make their subterranean retreat. Maybe it makes sense because their predators may be asleep, but why even hang out? Is there more food? Is it cozy up on the surface? What is it is about nighttime that makes them so much more bold.