As the sun rose, I noticed a group of alligators in this marshy section of the freshwater lagoon at Huntington Beach State Park but didn’t realize why they were there. Then one suddenly lurched forward and scooped up a little crab from the mats of organic material (algae? bacteria?) floating in the water, and then another did it, and another. It was remarkable how quickly they would go from floating motionless to catching the crabs and back to floating motionless.