The cane toad is native to central and South America, but in the 1930s it was brought to Australia to eradicate a beetle decimating sugar cane crops. Instead, the poisonous toad proliferated across the continent, killing every predator that ate it. In turn, marsupials, snakes, and northern quolls began dying off en masse. Experts feared the toad explosion would eclipse competing birds and reptiles. Biologists declared defeat and Down Under braced for the mass elimination of species.
Except it never happened. As New Scientist reports, the toads are being absorbed into the environment without the devastating effects originally predicted. Richard Shine is an invasive species researcher at the University of Sydney who has studied the cane toads. As he told New Scientist, "People saw these ugly creatures moving across tropical Australia and common sense said there was going to be a huge disaster. But it just hasn't happened at the scale that we feared." Other experts agree that “the system seems to be absorbing the toads” and the impact is much less severe than originally thought.
How is this happening? Biologist point out that when a cane toad arrives new to an area, predators will eat them. Both predator and toad will die off, having eaten and been eaten. But who remains is a bit more judicious in the next round of sampling. Also, young cane toads are less toxic than adult cane toads. So while a predator might get a nasty digestive issue from eating a young cane toad, they won’t necessarily die.
The cane toad, also called the “Giant Toad” and the “Marine Toad,” is as voracious as the cane beetle it is named after. It consumes the crop-decimating beetles, as well as small reptiles, rodents, birds, and even dog food. Their glands secret a white toxin that is poisonous to any animal, including humans, that eats it. Even licking the toad can result in serious illness or death.
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