Some species of pigs are much more 'attack prone' than others, but all can and will, sometimes, attack. Both bushpigs and the true Eurpoean boars tend to attack far more frequently that any of the others species I've hunted.
Out of the untold numbers of pigs of verious species I've shot, I've been 'routed out' a few times, but never personally had a truly close call. However, one fellow I was hunting with was ripped from mid-calf to mid-thigh by a big European-cross boar, as well as suffering numerous smaller wounds. As soon as the arrow hit, the boar came for him; cornering him. The fellow had a Ruger Blackhawk .357 with him, and emptied it into the boar, with the muzzle literally touching the boar. Six rounds of 158 grain jacketed semi-wadcutters (all into the thorax, but with none exiting) slowed the boar down, but it still stayed at him for a few more seconds before staggering away. It went several yards away before finally going down.
It took a while to get the fellow to the hospital, and he lost a fair amount of blood. I'm not sure that he could have gotten out of the woods by himself. I can't remember the number of stiches required to close the wound, but it was a couple of hundred, and his knee was perminently damaged.
Though the vast majority of hogs will never show any agression, don't under rate their POTENTIAL to turn nasty on you, doing real damage.
Ed
TGMM Family of the Bow