Mutant cane toads

Up to 20 per cent of cane toads in certain areas in Gladstone were found with "malformations", compared with 1 per cent of the population in non-urban areas.

"Cane toads are to the fresh water environment, what canaries were to coal mines," Mr Wilson said.

High exposure to ultraviolet radiation and parasites, as well as chemical runoff and airborne pollution can contribute to abnormalities in the amphibians.