The sanctuary is home to many coastal and off-shore birds that feed in the Gulf of Mexico and Atlantic Ocean. These birds fly to the sanctuary's islands, where they nest in the mangroves and coastal trees. Birds found in the sanctuary include the Arctic Peregrine falcon, bald eagles, Roseate Tern, Florida sand hill cranes and the Cape Sable seaside sparrow.
Many invertebrates make their homes in the sanctuary's trees and shallow waters. Invertebrates lack an internal skeletal system and have an exterior one or one filled with membrane fluid. Mollusks such as snails can be found on land; clams and sea cucumbers can be found in the sanctuary's waters. Other invertebrates found in the sanctuary include crabs, shrimp, sponges, jelly fish, butterflies and worms. Many water invertebrates live among the corals, where they can feed and seek shelter from predators.
Florida is known for its many reptiles, including the American alligator, sea turtles and lizards. Many of these can be found in the waters, on sandy beaches and along the rivers' shorelines. Five of the seven sea turtles found worldwide nest at the Florida Keys National Marine Sanctuary, including ridley, green, leatherback, loggerhead and hawksbill. Other reptiles found in the sanctuary include the Florida brown snake, Key mud turtle, Miami black-headed snake and American crocodile.
Several mammals are found in the water and throughout the sanctuary's mangrove forests. The Florida manatee thrives in warm water found year-round at the sanctuary and it has been seen in shallow waters feeding on sea grass. Sei, blue, fin, humpback, right and sperm whales make their way through the sanctuary. Other mammals include the Key Largo wood rat, Key deer, silver rice rat, Key Largo cotton mouse and Lower Keys marsh rabbit.
