An animal like that would probably be dangerous. Being, most likely, a released or escaped pet, it has no fear of man. Personally, I'd drive a couple of slugs through it's chest from a safe range. A .22 would kill it, but I'd use something a bit heavier myself. Start thinking 30-06 and up, many african countries have a .40 cal minimum. Even though everyone around you ignores it, it's still a potential danger to anyone who sets foot on that island. I would contact whatever are the proper authorities in your area and if they refuse to take action, I'd do it myself.