"Native to South and mainland Middle America), Cane toads were introduced to Australia from Hawaii in June 1935 by the Bureau of Sugar Experiment Stations, now the Sugar Research Australia, in an attempt to control the native grey-backed cane beetle (Dermolepida albohirtum) and French's beetle (Lepidiota frenchi).[3] These beetles are native to Australia and they are detrimental to sugar cane crops, which are a major source of income for Australia. Adult cane beetles eat the crop's leaves, but the main problem is the larvae, which feed on the roots. Adult cane beetles have a heavy exoskeleton and their eggs and larva are often buried underground, making them difficult to exterminate. Furthermore, conventional methods of pest control, such as pesticide use, would eradicate harmless species of insects as well, making it an unsatisfactory method.[4] Cane toads were to replace the use of pesticides like arsenic, pitch and copper. The success of using the moth Cactoblastis cactorum in controlling prickly pears in Australia also contributed to hopes for the cane toad.[5]
The cane toads bred immediately in captivity, and by August 1935 more than 102 young toads were released in areas around Cairns, Gordonvale and Innisfail in northern Queensland. More toads were released around Ingham, Ayr, Mackay and Bundaberg. Releases were temporarily limited because of environmental concerns but resumed in other areas after September 1936. Since their release, toads have rapidly multiplied in population and now number over 200 million and have been known to spread diseases affecting local biodiversity.[6]Unfortunately, the introduction of the toads has not only caused large environmental detriment, but there is no evidence that they have affected the cane beetles that they were introduced to prey upon. The toads have steadily expanded their range through Queensland, reaching the border with New South Wales in 1978 and the Northern Territory in 1984. The toads on the western frontier of their advance have evolved larger legs;[7] this is thought to be related to their ability to travel farther. As a consequence of their longer legs, larger bodies, and faster movement, about 10% of the leading edge cane toads have also developed arthritis.[8] It was estimated that cane toads migrate at an average of 40 kilometres (25 miles) per year as of 1994,[9] but new research in 2014 indicated that the migration rate had increased to 60 km per year on the western front.[10]"