How did rabbits become known as an invasive species or pest in Australia whereas it’s not the case elsewhere in the world?
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For rabbits, their evolutionary strategy is to make as many babies as often as possible. Make more offspring than predators can hunt and the rabbit’s DNA can be passed down. In native areas, rabbit populations are some of the main prey animals for things like hawks, wolfs, wild cats, feral dogs, feral cats, etc. They are hunted, killed, and eaten so often that only a few of the rabbits born actually live to reproduce again. There is a balance there.
In Australia they had much less pressure from predators. There were predatora hunting them, but the number of predator animal species and their population size was much less. So more rabbits were surving to breed again than would’ve normally in their native habitat.
In the rest of the world there are lots of predators that keep the rabbit population down. Primarily foxes but also lynx, falcons and other canines, cat species and predatory birds. For example the number of predatory species in southeast Asia means that the rabbits will not get established there, yet.
In Australia there is no big predators that will hunt rabbits. So the rabbits are able to spread uncontrollably. They are eating the plants that various other animals rely on for feed and can therefore become responsible for extermination of other species. But if we introduce predators to Australia to deal with the rabbits these predators will also hunt other native species and can equally be responsible for the extermination of the species we are trying to save.
Rabbits are an invasive species in the UK, the major difference is that the UK had similar predators around as mainland Europe, mainly hunting hares, so the population was controlled by local predators. Australian predators didn’t evolve to hunt rabbits so the population exploded.
An “invasive species” is a life form (plants and animals can be invasive) that doesn’t have any natural predators in the new environment. The things that keep its population in check in its native environment don’t exist in the new place. So it just breeds and breeds and breeds.
Rabbits are native to other parts of the world. It’s the same reason I’d be an immigrant in Australia, when that’s not the case in my home country. You have to not be native to be an invasive species