Australia battles cane toad spread A young Bufo marinus (Cane Toad). Darwin, Northern Territory, Australia. Credit: Bidgee/Wikipedia BRISBANE, Australia, April 9 (UPI) -- A cane toad cull in Australia saw thousands of volunteers taking part in an effort to control the invasive animals regarded as poisonous pests, officials said. Cane toads were introduced to Australia 75 years ago in an effort to control beetles threatening agricultural crops, but the experiment failed and toad numbers have swollen to an estimated 200 million. The toads secrete a toxin that can kill predators that are not adapted to eating them, making them a growing nuisance, officials said. "They're one of the most destructive creatures and the most disgusting creatures and one thing they're doing is they're killing our native wildlife and they're taking over our habitat," Queensland politician Shane Knuth told the BBC in justifying the cull. The toads were introduced into Queensland in the 1930s but their numbers have grown dramatically and they are spreading south in Australia because there are almost no natural predators that can kill them off, experts said. Climate change may help account for their unstoppable southern migration, they said.