I sit on a rock in an artificial lagoon, watching workers feed rays. “One for Pinky!” a worker calls as she throws a fish to a large pink whipray. Another woman notes the treat on a clipboard. There’s only one pink whipray in the lagoon, but I’m really impressed when the keepers can tell the five spotted eagle rays apart. These tropical rays can reach 10 feet wide and 16 feet long. Despite looking pretty flat, they tip the scales at more than 500 pounds. Here, the biggest eagle ray we...