I don't believe these are the average farm pig that has just turned feral. If I'm reading all of the articles correctly, they are wild boars that were domesticated in Europe and then brought over during the whole diversification era of farming. Emu, ostrich, elk for example.
These little buggers are curious and found ways out of their pens and returned to the wild.
But I'm not an expert. Its all just stuff I found on the web... and we all know what that's like !
All I know.. is I want to get one and have one hell of a bbq this Canada Day.