Goats betray their fellows, then pay the price

On an island off South Australia, a population of feral goats, descended from animals brought by settlers for their meat and milk, is following the usual routine of invasive species the world over. They're eating their way through the native plants, including one that's the main food source for the endangered black cockatoo.

By itself, hardly unusual enough to be worthy of mention. But here's where the really bad animals come into the story: the eradication effort, which involves what's being called "Judas goats."

From the Australian Broadcasting Corp:

The unwitting traitors are shipped over from the mainland, sterilised, fitted with radio tracking collars and released.

Project officer Nick Markopoulos says the program exploits the animal's sociable nature.

"Generally the goat will have about a week's sulk and once it gets over its week of sitting down and just adjusting itself to the new environment it's been released into, it will go off ... and find friends," he said.

"The feral goats are quite happy to accept them into their mobs and they fit right in."

The radio collars allow officials to find the group of feral goats and then, let's just say, they don't gather them up and take them to a goat shelter and adopt them out.

But what the Judas goats don't know is that they're going to pay the price for their collusion:

Mr Markopoulos predicts the island's feral population will be eradicated in a year.

Once they have done their job, the judas animals will also be destroyed.