Nonnatives - Giant Toad

Giant Toad - Bufo marinus

Florida's Nonnative Wildlife. Species detail.

First year: 1957

Extirpated year: 

Established status: Populations are confirmed breeding and apparently self-sustaining for 10 or more consecutive years.

Estimated Florida range: 21 counties  At least 10 years, 1 county  Not reported breeding

Statewide trend: Unknown status

Giant Toad
Photograph by Kevin M. Enge © 2003

Threats to natives: Voracious feeders that will prey upon small vertebrates. They will feed on leftover cat and dog food in suburban areas and will even scavenge garbage and discarded vegetable matter (Alexander 1964, Krakauer 1968). Their skin-gland secretions are highly toxic and can sicken or even kill animals that bite or feed on them, including dogs, cats, and native mammals, birds, and snakes. The skin secretions may irritate the skin or burn the eyes of human beings who handle them. They compete with native frogs and toads for food and breeding areas. Consumption of toad eggs causes mortality of tadpoles of other Florida frog species, particularly the green treefrog and southern leopard frog (Punzo and Lindstrom 2001).

Species Account: The giant toad primarily occurs naturally from the Amazon Basin in South America north to the Lower Rio Grande Valley in Texas. The Florida population is probably of Colombian origin and is the result of pet trade escapes and deliberate introductions (Bartlett and Bartlett 1999). In 1936, the University of Florida's Agricultural Experiment Station released 200 giant toads from Puerto Rico at Canal Point and Belle Glade in Palm Beach County to control sugar cane pests, but the toads disappeared in less than 1 year (Riemer 1958, Krakauer 1968). Two other attempted toad introductions in the 1940s by sugar companies at Clewiston, Glades County, and Pennsuco, Dade County, also failed (Duellman and Schwartz 1958, Riemer 1958, Krakauer 1970). The present population originated from the accidental release in 1955 of approximately 100 toads by an importer at the Miami International Airport (King and Krakauer 1966). These toads spread when a canal was constructed in 1958 linking the Blue Lagoon with South Florida's extensive canal system. In south Florida populations, female toads are commonly up to 18 cm (7 in) long, but more northerly populations tend to have smaller individuals. The maximum recorded length for the species is 23.8 cm (9.4 in). The ground color varies from red to brown, and there may be a pattern. The immense parotid glands angle downward onto the shoulders and exude a milky white toxin when the toads are attacked. The mating call is a low-pitched, rattling trill that begins with spring rains and is given from canals, flooded ditches, shallow pools, and fish ponds in urban, suburban, and agricultural areas (Bartlett and Bartlett 1999).

Habitats: Exotic plant community, Low density suburban development, areas peripheral to core urban areas, and small towns, Agricultural habitat, Recently disturbed, early successional community, Rockland Hammock

 
Region First Year Extirpated Year Breeding status Notes
SOUTHWEST ?

 

At least 10 years

 

SOUTH 1957

 

At least 10 years

 


County First Year Extirpated Year Breeding status Notes
BROWARD 1966

 

At least 10 years As far north as Hollywood (King and Krakauer 1966)
DADE 1957

 

At least 10 years The first mention of giant toads in Florida is by Neill (1957), but he did not specify a county
HILLSBOROUGH 1956

 

At least 10 years Tampa (Rossi 1981, Conant and Collins 1991)
MARTIN 2002

 

Less than 10 years Port Mayaca (K. Enge, FFWCC, Quincy, personal observation); FLMNH specimen
MONROE 1970

 

At least 10 years Stock Island (Krakauer 1970), Key West (Wilson and Porras 1983), and Key Largo (Meshaka et al. 2004)
OKEECHOBEE 1970s

 

At least 10 years Okeechobee (Meshaka et al. 2004; Krysko et al., in press)
PALM BEACH 1968

 

At least 10 years (Krakauer 1968)
PASCO 1991

 

At least 10 years Dade City (Stevenson and Crowe 1992c)
PINELLAS 1956

 

At least 10 years Tarpon Springs (Rossi 1981)
CITRUS ?

 

Not reported breeding (Meshaka et al. 2004)
HIGHLANDS late 1970s

 

At least 10 years Lake Placid (Meshaka et al. 2004)

 References

Alexander, T. R. 1964. Observations on the feeding behavior of Bufo marinus (Linne). Herpetologica 20:255-259.

Bartlett, R. D., and P. P. Bartlett. 1999. A field guide to Florida reptiles and amphibians. Gulf Publishing Company, Houston, Texas. 278pp.

Conant, R., and J. T. Collins. 1991. A field guide to amphibians and reptiles of eastern and central North America. Third edition. Houghton Mifflin, Boston, Massachusetts, USA. 450pp.

King, F. W., and T. Krakauer. 1966. The exotic herpetofauna of southeast Florida. Quarterly Journal of the Florida Academy of Sciences 29:144-154.

Krakauer, T. 1968. The ecology of the neotropical toad, Bufo marinus, in south Florida. Herpetologica 24:214-221.

Krakauer, T. 1970. The invasion of the toads. Florida Naturalist 43:12-14.

Meshaka, W. E., Jr., B. P. Butterfield, and J. B. Hauge. 2004. The exotic amphibians and reptiles of Florida. Krieger, Melbourne, Florida. 166pp.

Neill, W. T. 1957. Historical biogeography of present-day Florida. Bulletin of the Florida State Museum, Biological Sciences 2:175-220.

Punzo, F., and L. Lindstrom. 2001. The toxicity of eggs of the giant toad, Bufo marinus to aquatic predators in a Florida retention pond. Journal of Herpetology 35:693-697.

Riemer, W. J. 1958. Giant toads of Florida. Quarterly Journal of the Florida Academy of Sciences 21:207-211.

Rossi, J. V. 1981. Bufo marinus in Florida: some natural history and its impact on native vertebrates. M.A. Thesis, University of South Florida, Tampa, Florida. 75pp.

Stevenson, D., and D. Crowe. 1992. Bufo marinus (giant toad). Herpetological Review 23:85.

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