The Cuban tree frog (Osteopilus septentrionalis) is a prominent non-native species now widespread across Florida. This large amphibian represents a significant ecological shift in the state’s natural landscapes. Its noticeable presence often leads to questions about its origins and how it became so established. This article explores the species’ initial home, its journey to Florida, the factors enabling its proliferation, and its impacts on native ecosystems.
The Frog’s Original Home
The Cuban tree frog is indigenous to several Caribbean islands, including Cuba, the Isle of Youth, the Cayman Islands, and the Bahamas. These tropical environments offer high humidity and temperatures generally above 10°C, where the frogs thrive in moist habitats. They often reside in trees and shrubs, adapting well to human-modified settings like gardens and buildings.
The Journey to Florida
The Cuban tree frog’s arrival in Florida was largely accidental and human-mediated. They likely first reached the Florida Keys as stowaways on cargo ships from the Caribbean. Early confirmed records date back to the 1920s in Key West, with establishment on the mainland in Miami by the early 1950s. These amphibians often hitchhike in shipments of ornamental plants, building materials, commercial goods, or on vehicles like cars, trucks, and boats, facilitating their unintended transport.
Why They Thrived and Spread
Once in Florida, several biological characteristics allowed the Cuban tree frog to thrive and spread rapidly. They possess a high reproductive rate, with females laying thousands of eggs multiple times a year, sometimes over 10,000 to 16,000 eggs in a single season. Their eggs hatch quickly, often within 30 hours, and tadpoles complete metamorphosis in about a month, contributing to rapid population growth. These frogs are generalist predators, consuming a wide variety of prey, including insects, spiders, snails, millipedes, other frogs, lizards, and small snakes.
They are also highly adaptable, capable of surviving in various habitats, from natural woodlands to urban and suburban areas, and can tolerate a wide range of temperatures and even brackish water. Florida’s ecosystem lacked effective natural predators to control their populations, further contributing to their success. Human activities also inadvertently assist their secondary dispersal within Florida, as they continue to hitchhike on vehicles and landscaping materials.
Ecological Ramifications
The Cuban tree frog has significant negative impacts on Florida’s native ecosystems and biodiversity. Their voracious appetite leads them to prey on native frog species, lizards, and even small birds, directly reducing native populations, with native tree frogs like squirrel tree frogs being particularly susceptible. They also outcompete native amphibians for food and breeding sites, as their tadpoles are superior competitors to those of some native frog species. The skin secretions of the Cuban tree frog can be irritating to humans if they contact eyes or mucous membranes. These secretions are also toxic to pets, potentially causing excessive salivation or vomiting if ingested.