This morning there were groups of rays patrolling the beach, working together to catch the little fish that congregate near the shore:

 

These rays are not bothered by people at all, they simply weave in and out around the swimmers, always staying as a group, sometimes close to shore and sometimes just beyond the sandbar--wherever there are schools of little fish.  I'm still trying to figure out what kind of rays these are; are they lesser devil rays, because of their dark color and the fact that they're scooping up the the little fish with forward-facing mouths?  Or are they cownose rays, which are brown, with downward-facing mouths, and which eat crustaceans and mollusks?  It's very confusing.  These rays are definitely eating the little fish because sometimes the fish jump right out of the water to get away...

I've seen stingrays at the beach as well, usually in the summer, but these are sand-colored and hide just under the sand near the shore to catch their prey.