I know nothing about hog hunting, we have little to none here in New England, but I' m curious, what would be the evolutionary advantage to this " shield" . Being a biologist makes me wonder, does it fully cover vitals or are the vitals further back as stated? If the vitals are further back what is the shield for? I' m sure it didn' t come to be to deflect expandables. Most natural kills by predators would probably be to the neck region, does it extend up around the neck? Is it just a callous built up from wallowing and rubbing. Like I said, just curious, sounds like it serves some purpose that would have come up thousands of years ago. Thanks