Why did the cane toad experiment fail?

In 1935, cane beetles were devastating the sugar industry in Australia. The grubs would burrow into the ground and destroy the roots of the sugar cane, causing it to die before it could be harvested. Farmers and scientists were desperate for anything that might work. They imported approximately 100 cane toads into Australia. They had discovered that the cane toads ate cane beetles

• but only when they were in a laboratory, hungry, and offered no

other food. Once arrived in Australia, the toads found other food sources (like smaller beetles and moths) much more to their liking. They reproduced prolifically. In the simplest sense, the experiment failed because the cane toads did not work as a biological control method. They did not eat the cane beetles when there was another food source available, and there was always something more palatable for them to eat. In the broader sense, it was a failure because it has been an environmental disaster for Australia. Cane toads eat anything, and outcompete native species for food. They are poisonous, so species that prey on non toxic native frogs (such as snakes and carnivorous birds, lizards and mammals) eat the toads and die because very few have learned to recognise them as harmful. Cane toads produce far more eggs in proportion to body size than most native frogs, and will breed in stagnant or brackish water that most frogs will reject. Toad tadpoles are extremely aggressive, and cause damage to local waterways. They eat the spawn and tadpoles of most native frog species and strip away all the food, starving any that are left. They develop rapidly and overrun the land. Cane toads are extremely adaptible. They can live in virtually any habitat as long as they can find breeding sites (any still water) and food (almost any insect). They have spread over vast swathes of the Australian north. They are ugly, they kill pets, and they have caused immeasurable damage to the environment. The cane toad infestation in Australia was the result of a poorly designed experiment which was implemented far too soon.