Due in part to its prevalence in the exotic pet trade,[12] Florida has a large number of non-native species. The Florida Fish and Wildlife Commission tracks 31 species of mammals,[13] 196 species of birds,[14] 48 species of reptiles,[15] 4 species of amphibians,[16] and 55 species of fish[17] that have been observed in the state. Many of the identified species are either non-breeding or stable populations, but several species, including the cane toad (Bufo marinus),[18] Gambian pouched rat (Cricetomys gambianus),[19] Nile monitor (Varanus niloticus),[20] and Burmese python (Python molurus bivittatus),[21] have created significant impact on the delicate ecosystems of the state, especially in the tropical southern third of the state.