yeah the wallowin in the mud and rubbin on trees is real typical of hogs. hogs are not strictly nocturnal but it all depends on weather and moon phases and so on..... One way that you could get him is bait em in with some fermented corn and place itin the area where yer trail cam is, then just sit up in a stand and pick em off. there is a recipe in this forum for the fermented corn mixture
http://huntingnet.com/forum/tm.aspx?m=3008749