Australia's punishing climate has made invasive cane toads tougher than their country of origin counterparts, a University of Sydney study has found and are likely to spread "everywhere" across the country.
PhD candidate Georgia Kosmala sat inside an "oversized fridge" and recorded the stamina and temperature adaptability of cane toads from native populations in Brazil and invasive populations in Hawaii and Australia.
Ms Kosmala said the Aussie battlers performed better than their native South American counterparts.
"We had a circular track and that was put in a temperature control room...that fit the track, me and the toads," she said.
"They (the Australian cane toads) were able to withstand dehydration a lot better and were able to withstand colder temperatures and hotter temperatures...that are not within the native range climate.
"If you were to put a native toad today in one of the ranges that the Australian cane toads occupies, he would probably do very poorly and that is because toads in Australia are adapted to those climates and those conditions."
Ms Kosmala said the Haiwaiian toads performed "a lot worse" and attributed it largely to their living conditions that had turned them into "couch potatoes".
"The toads are confined to man-made settings like golf courses where they have constant water from sprinklers...they are very comfortable," she said.
"They don't venture around or roam too far from those places...we think that that made them suffer less of a challenge from the actual climate and had less adaptation happening.
"In Australia...those man-made settings were not there and they spread all over the place, they were forced to adapt."
The study, published in the Royal Society Open Science, found the cane toad's tolerance to water stress and thermal stress had increased since their introduction from South America 82 years ago.
Their usual habitats range from sand dunes and coastal heath to margins of rainforest and mangroves and they are most abundant in grassland and woodland, according to the Australian Museum.
Ms Kosmala said it remained a "mystery" how much they could adapt and how far they could spread across Australia.
"There were a lot of studies that were posed...that they wouldn't reach Western Australia...they already halfway through northern part of Western Australia and they seem to be doing very well," she said.
"They keep surprising us, they keep doing better than we expected them to which is not good news for Australia.
"Right now I would say just predict they are going to be able to spread everywhere because they seem capable to do it.
"They have already reached the north of New South Wales so I say they could probably go much further down."