Cane Toad
© AP
The cane toad is famed for its indestructibility

In a contest between a toad and a crocodile, it seems obvious the croc will win. Not, though, if its adversary is a cane toad - the poisonous pests laying waste to Australian wildlife.

Researchers have found that, in some waterways in the Northern Territory, numbers of freshwater crocodiles have more than halved over the past two years. The reason is cane toads, which are fatal when eaten.

Professor Keith Christian, from Charles Darwin University, said: "A recent survey on the Victoria river showed that in a one-year period as many as 77 per cent of the crocodiles have died as a result of eating cane toads," he said.

Professor Christian said second-year data also showed evidence of a high death rate, which had dire implications for the species - "particularly in these long-lived species that take a long time to mature before they are reproductive." Since being introduced into Queensland in the 1930s, cane toads have spread across northern Australia.