Cat Island is a unique "T-shaped" island created by colliding Gulf of Mexico currents. Unlike the other Mississippi islands, Cat Island's sand beaches are backed by dense forests of slash pines and live oaks. Due to the dredging of the Gulfport ship channel, however, Cat Island has lost its natural westward flow of sediment which provided material for the island to combat erosion. Bayous and marshes on Cat Island are home to alligators and refuge to migratory birds.