Too Much Hopping Gives Toads Arthritis

Oct. 16, 2007 — Cane toads are paying a debilitating price for their invasion of Australia, researchers show. It seems the stress of constant movement has left many of the toxic pests vulnerable to severe arthritis.

Rick Shine and his colleagues at the University of Sydney have been following the reviled pests as they spread into the Northern Territory.

Their latest research, published online today in the journal Proceedings of the National Academy of Sciences, shows that roughly one in 10 of the largest toads are suffering severe spinal arthritis.

The arthritis is linked to infection with the common soil bacteria Ochrobactrum anthropi.

In part, the situation seems to have arisen because the toads have evolved longer legs to adapt to the invasion, Shine said.

"Frogs' bodies are not well designed for long distance athletic challenges.

"But because of the invasion process, the cane toads have evolved into these road warriors that are travelling every night during the wet season," he said.

During that season, the invasion front advances an average 130 meters (426 feet) each day, he says. For the toads, that means an extraordinary amount of physical wear and tear.

"There's a huge ball of bony tissue that's grown up around the joints," said Shine. "It substantially affects their ability to hop around."