Australia's most bothersome invader species may be the Cane toads (Bufo marinus), warty amphibians that tend to devour everything they can fit in their mouths, including lizards, mice, dog food, even other cane toads, and because they are poisonous, they have no natural predators (Stroh 2002). This amphibian, which can grow to roughly one-foot in length and weigh as much as ten pounds, is one of the many human-introduced species that is currently ravaging the ecosystem in Australia (Young 2000).

             The cane toad, originally from South America, was introduced by the sugar industry in 1935 in an attempt to control two sugarcane pests, the Grey Backed cane beetle and the Frenchie beetle, however the toad does not generally eat these particular insects, but has instead successfully devoured other native insects and micro-fauna to the point of extinction (Young 2000). It was also discovered sometime later, that the cane toads cannot jump very high, thus they could not eat the cane beetles which thrive on the upper stalks of the cane plants (Unwanted 2005). Moreover, the poisonous toad instantly kills any predator that attempts to eat it, particularly the quoll, Australia's marsupial cat, and giant native lizards, all the while its own population continues to proliferate as it out-competes native amphibians and spreads disease (Young 2000). The most effective solution to the cane toad problem has been the "Chill a Toad" program, which involves catching, refrigerating and killing them one by one (Young 2000). If unchecked, bioinvasion may ultimately mean the extinction of Australia's exotic wildlife and destruction of a major ecosystem, a disaster marked by the absence of native frogs (Young 2000).

             Cane toads are considered a major threat to biodiversity, not only because they out-compete native species for food and consume others, but their skin toxins kill .

             carnivorous predators that mistake them for local amphibians (Lunter 2004).