Information Last Reviewed Spring 2007
Native to South America, Central American, and extreme southern United States (Texas), cane toads are perhaps the most often intentionally introduced species in the world, primarily as a biocontrol agent for crop pests. In the United States, cane toads have become established in Florida, Hawaii and Puerto Rico. Native predators appear to keep populations in check, but some groups (mainly mammals) are susceptible to toxins produced by the toads. Significant adverse impacts have not been documented on native wildlife populations in the United States, but have in other countries (e.g., Australia). Control of target pest species (e.g. sugar cane beetles) by cane toads has not been achieved. Other common names for the species include giant toad, marine toad, and giant marine toad.
Short, squat body with relatively short legs
Dry, warty skin
Large, deeply pitted parotoid glands extend down the sides of body
Largest U.S. toad, sometimes exceeding 6" snout-to-vent length (specimens over 9" have been reported)
Largely nocturnal, but potentially active any time of day
Terrestrial as adults, aquatic as larvae (tadpoles)
Hop and walk
Adults are predators; tadpoles are omnivorous
Males vocalize to attract females when breeding; call is a slow, low-pitched trill
Excavates and becomes inactive during cool or dry weather
Cane toads exhibit typical true toad (Bufonidae) appearance, with dry, warty skin and relatively short legs; unlike frogs, which generally leap, toads typically hop. Adult cane toads are brown or grayish-brown dorsally with occasional whitish spots. Ventral coloration is yellowish, usually flecked with black. The back and legs are covered with spiny warts. Tadpoles are black dorsally and silvery-white with black spots ventrally.
True toad appearance (dry, warty skin, parotoid glands between the eyes) distinguishes the cane toad from all U.S. spadefoots, treefrogs, true frogs, and narrow-mouthed toads.
Large size, large parotoid glands extending far down the sides of body, and breeding call distinguish the cane toad from all other U.S. true toads.
Juveniles and young adults superficially resemble many Bufo species.
Cane toad life cycles include an aquatic larval stage and a terrestrial adult stage.
Aquatic, gilled tadpoles
After 45-60 days, tadpoles metamorphose into terrestrial juveniles. Sexual maturity is reached after one year
Reproduction occurs in temporary water bodies between early spring and autumn, usually following rains
Males attract females by calling (a slow, low-pitched trill)
Mating occurs in water; males clasp females and hold them in amphiplexus
Females release two strings of eggs while in amphiplexus; fertilization is external; eggs are surrounded by a gelatinous sheath that floats or wraps around vegetation
Eggs are tolerant of low to moderate salinities
Egg production ranges between 10,000 and 32,000 per female per season
Eggs hatch in three days
Forests with temporary or permanent standing water. Cane toads are limited to tropical and subtropical climates, with relatively high humidity and moderate temperature.
Successful in disturbed areas where introduced, including around buildings and in yards
Sensitive to cold climates
South America up to extreme southern Texas
North American Distribution
Native to southern Texas. Introduced to parts of Florida, Hawaii, and Puerto Rico.
Probable Means of Introduction
Intentional stocking for control of insect and rodent pests
Cane toads are voracious predators, feeding on invertebrates, other toads, frogs, lizards, snakes, small birds, and small rodents.
Reported to eat dog and cat food set out for pets.
Tadpoles feed on algae and aquatic plants, and filter organic material from the water; large tadpoles reportedly cannibalize their own species’ eggs.
Introduced cane toads are principally problematic in that they secrete toxic substances as a defense mechanism against predation.
Skin-gland secretions, especially those from the parotoid, are highly toxic
Mammalian predators, including dogs, cats, and native wildlife, may sicken and sometimes die after biting cane toads
Secretions may also irritate the skin or burn the eyes of humans handling cane toads
Probably compete with native amphibians for food and breeding sites
Probably impact native populations of reptiles and amphibians through predation
Probably impact populations of beneficial insects (e.g., honey bees) through predation
Introduced to control pest species (e.g., sugar cane beetles, albeit without success)
Exclusion from breeding sites (e.g., toad barriers)
Experimental efforts investigating the use of pheromones to disrupt breeding cycles are underway
Prohibit intentional stocking
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Krakauer, T. 1968. The ecology of the neotropical toad, Bufo marinus in south Florida. Herpetologica 24(3):214-221.
Krakauer, T. 1970. The invasion of the toads. The Florida Naturalist 12-14.
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