Amphibians (Phylum Chordata, Class Amphibia) are found in freshwater. Common methods of introduction include release of pets, escape from pet dealers, or intentional introduction for pest control. Potential impacts can include displacement, reduction, or extinction of native species. The Cuban treefrog, Osteopilus septentrionalis (pic 68k), was first introduced into Florida in 1931 as a stowaway in a shipping crate. Since then it has spread and become established throughout southern Florida. The Cuban treefrog has been shown to prey upon the native green treefrog, Hyla cinerea (pic 45k), and the squirrel treefrog, Hyla squirella (pic 44k).