Australian researchers have developed an "innovative method of conservation" for yellow-spotted monitor lizards. They trained the predators not to eat the highly toxic cane toads which could kill them in 30 seconds or less.
Cane toads are invasive species that came from South and Central America. In 1935, they were introduced to Australia and has spread across the northern part of the country. Cane toads spread by about 25 to 37 miles per year.
The species is so toxic that they can kill more aggressive and bigger predators that eat them. In fact, they are the cause of a catastrophic predator population decline, including Australian monitor lizards or goannas. The yellow-spotted monitors' population have decreased by 90 percent following cane toad invasions.
University of Sydney researchers devised a way to keep goannas from eating these highly toxic snacks. The research team offered non-lethal cane toads to the free-ranging monitors at northwestern Australia's Kimberley wilderness.
It only takes 30 seconds for a captured, adult cane toad to kill a monitor lizard. In the experiment, the younger and smaller cane toads made the monitors sick, but were not lethal enough to kill the predators.
After one or two cane toad meals, the monitors learned not to eat another toad. Following their exposure to smaller, non-lethal toads, majority of the trained 16 monitors learned to avoid the larger, lethal cane toads found in the wild in the span of the 18-month study. When the research ended, all the 31 untrained monitors died from cane toad invasion.
"We saw the goannas that had not had a negative experience with the small toad died very quickly. They all died within three months of the natural cane toad invasion arriving at the site," said lead researcher Georgia Ward-Fear.
The experiment gave the predators a chance to learn about the deadly snacks firsthand. It offers a simple conservation method for animals living in the wild. The research team presented a real evidence that the conservation strategy is realistic.
The study was published in the journal Biology Letters on Jan. 6.
Photo: Peter Gronemann | Flickr
