Killer Rabbits
You'd never think of rabbits as dreadful, destructive creatures, would you? Rabbits are cute and loveable. However, Australians discovered harm these cute creatures can do the hard way.
Rabbits were introduced to Australia in 1788 as food animals. By 1827, they were running around large estates, and in 1859, disaster struck. A man released 12 wild rabbits onto his property for hunting and he have thought that was harmless fun. But Australia has nopredators(捕食者)(adapt) to killing rabbits and none of the diseases that kept their populations control in Europe. The loose rabbits bred like, well, rabbits, and began to take over the countryside. Within a few decades, there were millions. By 1950, there were 600 million rabbits in Australia.
Six hundred million hungry rabbits could do real harm. They caused more damage than any other species introduced to the continent. They ate native plant species they disappeared. They competed for food and shelter with native animals. They caused the extinction or endangerment of numerous plant and animal species. And they were a nightmare for cattle and sheep farmers, animals couldn't get enough grass to eat and starved.
The rabbits did some good, of course. They provided food for poor families. They supported fur industries. But their impact on the environment and major livestock economy was too negative (ignore). People tried trapping them. They even built a huge wall against them. But (effective) weapon was a virus.
(test) multiple times, the deadly myxoma virus was released on Australia's rabbits in 1950. The virus had been developed very carefully to affect only rabbits. Nearly 100 percent of the rabbits who caught the disease (die). Populations fell. It was a huge success. Cattle and sheep farming recovered gradually, and threatened plants were better protected. Eventually, rabbits became resistant to the virus.