Cane Toad Introduction (1935)
Sugar farmers thought cane toads would save crops from beetle pests. The imported amphibians ignored the beetles completely. They rapidly multiplied across northern Australia instead. Native predators died after eating the toxic toads. Nothing stops their southward invasion decades later. This spectacular backfire demonstrates the dangers of introducing non-native species without understanding ecological relationships. The poisonous invaders now number in the hundreds of millions.
