This was taken in Hong Kong, but nearly every place on earth where pigs can escape into a forest, you end up with a ferral hog issue. That big ass hog may have been a small bald cuddly domesticated hog when it was younger. However, after a domesticated pig gets loose into the wild, they grow hair and tusks within only 1 years time. And their husks get bigger and bigger and their coat gets thicker and thicker.
Another issue are the hybrid hogs that are popping up now. A ferral hog and wild boar will mate and the result is even greater natural size and a meaner than average disposition. To top it off, hogs are smart as fuck, much smarter than dogs, so they are quite the adversary.