Some blue-tongue lizards in eastern Australia can dine on the cane toads and live, though. Oddly enough, they might owe their immunity to another invasive species.

An ornamental plant native to Madagascar called mother-of-millions (Bryophyllum delagoense) is common in eastern Australia, and has also become part of the lizards' diet. The plants' flowers contain a poison similar to bufadienolide. Rick Shine at the University of Sydney, Australia, suspected that lizards which have already gained immunity to this toxin might be in a better position to withstand the toad toxin too.

His team caught 75 lizards that lived in areas containing either the toad and the ornamental plant, just one of the two, or neither of the toxic invaders. Shine injected toad poison into the lizards, administering a dose high enough to provoke a reaction, but not enough to kill the animal. His team then timed how fast the lizards could swim 50 centimetres.

Blue-tongue lizards from areas containing mother-of-millions were affected to a lesser degree than any others. This was true even for lizards that lived in regions of eastern Australia that contain no cane toads.