Why are cane toads a problem in Australia?
Cane toads are a problem because they are poisonous to many native animals that eat them. Introduced in 1935 to control beetles in Queensland's sugarcane, they have spread across northern Australia.
In 1935, 102 toads from Hawaii were brought to Gordonvale, near Cairns. They failed to control the cane beetles, but they bred rapidly in the warm climate.
The toads have toxic glands on their shoulders. Predators such as quolls, goannas, freshwater crocodiles and snakes often die after eating them.
Spread and response
Cane toads have spread west through the Northern Territory into the Kimberley and south into New South Wales. Their invasion front moves tens of kilometres each year.
Scientists train quolls and goannas to avoid toads by feeding them small, non-lethal toad meat treated to cause nausea.
Community groups hold toad busting events.
Toads also compete with native frogs for food and can poison pet dogs that mouth them. Their numbers are highest just behind the invasion front, and some predators adapt over time, so populations of goannas and quolls may slowly recover after the first wave. Researchers are also studying genetic approaches to reduce toad numbers, but no single solution has yet stopped their spread across the north.
Did You Know?
Female cane toads can lay up to 30,000 eggs at a time.