We have rabbit proof fences, one of which is the longest fence in the world.
Rabbit-proof fence - Wikipedia
, "The introduction of a few rabbits could do little harm and might provide a touch of home, in addition to a spot of hunting", a prediction which has not aged well.
Rabbits in Australia - Wikipedia
I live in a massive sport hunting area... It's even a huge part of this area's economy (I don't care to hunt, maybe if I was starving) ...
Anyway to increase interest people brought in some Russian boars... Over time those animals got in with domestic pigs and now we have this mass of half wild hogs that will hurt you (or kill you) if you entice them, and destroy everything in sight. On top of that only a high powered rifle will kill them... Something small caliber will get you attacked...
Every sow starting at nine months old can have up too 22 piglets a year! It's insane and it was not watched when this started, so now our wild hog population is so bad the state hunts them from helicopters to try and drop the numbers killing massive amounts at a time and nothing is seeming to help.
The destroy crops, damage property, we even had them at the golf course and they rooted up three golf greens in one night, breaking sprinklers, it is unthinkable in the damage they cause. That one incident of thousands was about 50,000.00 and a loss of player interest, and it was tough for a while...
They are such a dense animals... Sometimes when a car hits a large one, it will total the car (or cause it to rollover) which has resulted in many human deaths, as herds of them get out in the roads and bar ditches at night.
We also have a massive deer population and many of them have been breed and genetically engineered to have massive horn racks... They too are very scary things to dodge at night (or in the day) while driving here.
So now we are basically surrounded by animals bred by people and there are so many that the "sport" is not much of a "sport" anymore... Its more of an eradication process that is sad, but I suppose necessary because humans interfered with our natural eco system an in a very short time made a huge mess. Now its a gross, sad, mess to try and fix this...
Cause and Effect... at work right before my own eyes. : )