I have seen some big adult boars that didn't look all that big in the tummy before. They had some really thick front leggs on them though as well as a very wide looking head. Sometimes they can fool you when looking at the size of the tummy compared to proportion. But as others have stated when you see a big bear you will know it is a big bear without much of a doubt about it.. Shoulder hiegth is one way to tell as well sometimes..