TOAD.
"The cane toad in Australia is regarded as an exemplary case of a "feral species" — others being rabbits, foxes, cats, and Giant Mimosa. Australia's relative isolation prior to European colonization and the industrial revolution — both of which dramatically increased traffic and importation of novel species — allowed development of a complex, inter depending system of ecology, but one which provided no natural predators for many of the species subsequently introduced. The recent, sudden inundation of foreign species has led to severe breakdowns in Australian ecology, after overwhelming proliferation of a number of introduced species for which the continent has no efficient natural predator or parasite, and which displace native species — in some cases these species are physically destructive to habitat as well."
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