At dusk in Ría Lagartos, Mexico, I watched a trio of flamingos wade through the shallow waters of this vast coastal wetland. They feed on brine shrimp and other small organisms, filtering food from the water with their specialized bills. Ría Lagartos, meaning “Alligator River,” is neither a river nor home to alligators, but it is an important refuge for flamingos and crocodiles.