Unwelcome and unpredictable: the sorry saga of cane toads in Australia

The history of biological invasions, and of attempts to combat them, is dominated by stories of futility. Especially in the case of invasive species that have a high public profile, like the cane toad (Rhinella marina) in Australia, the voices of scientists often have been drowned out in the roar of populist political debate. There have been many failures by science as well, beginning with the initial importation of toads for biocontrol, and extending through failed attempts to predict future patterns of toad colonisation and impact, or to devise practical means to ameliorate that impact. In our (highly biased) opinion, progress in understanding such issues and in developing effective means of toad control emerged only from detailed ecological research on toad biology, rather than enthusiastic but poorly informed attempts to find better ways to slaughter toads. The story of cane toad science in Australia is a cautionary tale for our ability to predict the future, because, to date, we have done an abysmal job of doing so. ‘In the biological control of insect pests, … perhaps more than in any other [field], the path to successful achievement is strewn with the remains of optimistic attempts which have ended in abject failure. … Such a project is not to be embarked upon lightheartedly, but only after the most mature consideration, since a false step may have most disastrous … consequences through the upsetting of the whole biological balance.’ R. W. Mungomery (1934, p.5), written the year before he brought cane toads to Australia.