Feral cats in Australia have pushed many species of native marsupials and birds to the edge of extinction. In response, Australia has bounties to encourage people to shoot feral cats, and has a massive program of poisons baits. Now ecologist John Read has designed a laser-sighted robot to spray poison onto cats, and only onto cats, with the expectation they'll lick their fur and die.
With four laser rangefinders, the trap detects when something moves in front of it. If it’s taller than a cat – perhaps a dingo or a koala – the top rangefinder will be triggered and it shuts down. Similarly, a rangefinder at the bottom needs to be able to see between the cat’s legs, meaning a low-slung animal like a wombat or a quoll won’t trigger it.
Finally, two rangefinders at the front and back of the trap need to be triggered simultaneously, indicating something the length of a cat has moved in front of it.
Australia's first robot cat killer, has already been installed in a nature reserve in south-west Queensland. The Australian government says there are approximately 20 million feral cats in the country, and that they threaten to push over 100 species over the edge, as each cat eats between three and 20 native animals a day. The poison used is sodium fluoroacetate.