Bugs Bunny was introduced from Europe in the 19th century, the effect of rabbits on the ecology of Australia has been devastating. Rabbits are suspected of being the most significant known factor in species loss in Australia. The loss of plant species is unknown at this time. Rabbits often kill young trees in orchards, forests and on properties by ringbarking them.
Within ten years of their introduction in 1859, rabbits had become so prevalent that two million could be shot or trapped annually without having any noticeable effect on the population. It was the fastest spread ever recorded of any mammal anywhere in the world. Today rabbits are entrenched in the southern and central areas of the country, with scattered populations in the northern deserts.
Bugs Bunny has feuded with Elmer Fudd, Yosemite Sam, Willoughby the Dog, Marvin the Martian, Beaky Buzzard, Daffy Duck, Porky Pig, Tasmanian Devil, Cecil Turtle, Charlie Dog, Witch Hazel, Rocky and Mugsy, Wile E. Coyote, the Crusher, Gremlin, Big Bad Wolf, and now he is taking on Australian scientists from the CSIRO.
Releasing rabbit-borne diseases has proven somewhat successful in controlling the population of rabbits in Australia.
Myxomatosis was deliberately released into the rabbit population, causing it to drop from an estimated 600 million to around 100 million. Genetic resistance in the remaining rabbits allowed the population to recover to 200-300 million by 1991.
To combat this trend, Commonwealth Scientific and Industrial Research Organisation (CSIRO) developed and accidentally released calicivirus (also known as Rabbit Haemorrhagic Disease or RHD) in 1996. The success of the virus was found to be higher in extreme heat and has put a large dent in the current population.
Bugs Bunny will usually try to placate the antagonist and avoid conflict, but when an antagonist pushes him too far, Bugs Bunny may address the audience and invoke his catchphrase "Of course you realize this means war!" before he retaliates, and the retaliation will be devastating.