The cane toad, Rhinella marina, is a large amphibian and an invasive species in Florida. This non-native animal threatens local wildlife and pets due to its defensive capabilities. These toads are identifiable by their substantial size and prominent poison glands behind their eyes, which secrete a potent toxin.
Original Habitat and Early Introductions
Cane toads are native to a wide geographical range from the Amazon basin in South America, through Central America, and into extreme southern Texas. In their native environments, these toads are known for their voracious appetites, consuming insects and other small prey. This predatory behavior made them appear useful for agricultural pest control.
Cane toads were intentionally introduced globally, primarily to combat pests in sugar cane fields. Early introductions occurred in the 19th and 20th centuries, reaching locations such as Hawaii, Puerto Rico, other Caribbean islands, Australia, and the Philippines. These translocations established the cane toad as a biological control agent, setting the stage for its arrival in Florida.
The Florida Story: Intentional Release
The introduction of cane toads to Florida was largely intentional, driven by agricultural concerns in the 1930s and 1940s. Sugar cane growers sought a solution for pest infestations, particularly scarab beetles and their larvae, which damaged sugar cane crops. Early attempts, such as a 1936 release of 200 toads from Puerto Rico in Palm Beach County, were largely unsuccessful.
Despite these initial failures, other intentional releases continued into the 1940s by sugar companies in agricultural areas. An accidental release in the 1950s, when approximately 100 cane toads, imported from Colombia, escaped from a crate at the Miami airport, also contributed. Furthermore, accidental releases or escapes from the pet trade and biological supply houses in the 1950s and 1960s also contributed to their presence.
Establishment and Spread
Once introduced, cane toads successfully established breeding populations and began to spread across Florida, particularly in the southern and central regions. Florida’s warm, humid climate provides an ideal environment, allowing them to thrive and breed year-round.
Cane toads are highly adaptable, commonly found in human-modified habitats such as yards, golf courses, and agricultural areas. Their reproductive capacity is substantial, with females laying thousands of eggs in long, gelatinous strings, often between 8,000 and 35,000 eggs per clutch, and potentially multiple clutches annually. These eggs hatch quickly, and tadpoles develop into toadlets, contributing to rapid population growth. The relative lack of natural predators in Florida, combined with their opportunistic feeding habits, facilitated their successful establishment and expansion.