Cane toads have adapted to
hotter, drier conditions than
their native home range and may
also ‘hitch-hike’ across
desert barriers.
CSIRO Science Image/Alex Hyatt.

The introduced cane toad, currently impacting Australia’s northern ecosystems, may migrate further south than previously thought because of its ability to rapidly adapt to climatic conditions.

Mathematical modelling of future cane toad distribution carried out by Dr Ben Phillips and Professor Rick Shine from Sydney University’s School of Biological Science, with researchers from Yale University, indicated that cane toads will be able to live and breed in large areas ofWestern Australia (including Perth), South Australia (including Adelaide) and western Victoria, as well as in several pockets along the CNew South Wales coast.

‘Previous predictions of toad distribution in Australia were based mostly on the range of climatic conditions where toads live in their native range in Central and South America,’ says Professor Shine.

‘The toads have adapted rapidly to Australian conditions, and now tolerate much higher temperatures than was the case when they first arrived on our shores in 1935.

‘As a result, toads have managed to spread much further, into climatic zones also found widely through southern Australia – so there is no reason to think they will remain only in the tropics.’

Most of the potential range of the cane toad in southern Australia is separated from the toad’s tropical range by large expanses of desert, too dry for a toad to cross. But, warns Professor Shine, cane toads are ‘accomplished hitch-hikers, always willing to accept a free ride among rubbish or equipment
in the back of a truck’.

‘The sheer volume of traffic between tropical Australia and the south – especially given the current mining boom in Western Australia – means that small warty hitch-hikers may even now be heading south.’