SCIENCE LAB SHRIEKS : CANNIBALISTIC TOADS

 

CANNIBALISTIC TOADS 

Not just ugly, but an absolutely terrible dinner companion.

In Australia, poisonous cane toads have become their own worst enemies.

Scientists have long known that cane tadpoles devour their younger kin in the puddles and ponds they share, but the cause of cannibalistic behaviour has been a mystery, until now.

A study has found that cane tadpoles in Australia develop an insatiable appetite when they're exposed to a toxin found in cane toad eggs. It's the same toxin that makes toads poisonous.

Cane toads, native to South America and Central America, were taken to Australia in 1935 by scientists to try to reduce the number of cane beetles, which were causing problems for sugar cane farmers.

But the rapidly multiplying toads became pests that have squeezed native amphibians out of habitats.

The cannibalism was not seen in the toads' original range in the Americas.

''This is a unique case where evolution is extremely rapid and we can see it happening in real time,'' said Jayna DeVore, from the University of Sydney in Australia and an author of the study.

The study's authors argue that cane toads most likely evolved this cannibalistic response to their own toxins in Australia to reduce the number of other cane toads in their overpopulated new habitat. [ Annie Roth ]