Origin: Northern South
America, Central America, and Mexico
Impacts: The great toad, or cane toad, is considered
the most introduced amphibian in the world.
B. marinus is able to reproduce nearly year round. It was
originally introduced in an attempt to control insects such
as the greybacked cane beetle, Lepidoderma albohirtum, which
threatened sugar cane production. However, there is no evidence
that it has controlled any pest in Florida or Australia, where
it was also introduced to control insects. It is now considered
a pest species itself in Australia and the Pacific and Caribbean
The current population in Florida, thought to inhabit 6-10
counties, threatens native species. The great toad preys on
small invertebrates and will even scavenge in urban areas.
It out-competes native amphibians for food and breeding habitat
and also causes predator declines, since these predators have
no natural immunity to the bufotoxin it secretes. Cats, dogs,
native mammals, snakes, and birds are all at risk. Humans
may suffer skin rashes or eye irritation when contact is made
with the toad's skin.
The extensive canal system in Florida plays a major role
in the spread of this invasive species.
Photo courtesy of U.S. Geological Survey