This is how pig tusks fit together and self sharpen. They are also fairly deep set into the bone with another third or so of what you see being still embedded. When you corner them in hollow tree stumps or whatever, they thrash the head from side to side trying to rip you. Some of the boys use dogs with leather breast plates to catch em - some, the dud or stupid dogs mostly, don't last long.
I used to have a pig dog but it turned into to much of a killer - took on free lance jobs -by itself. Needless to say it ain't here no more, but it ain't.
Nowadays I just use bush skills and sneak up on them- sometimes I get them with a knife, sometimes a spear, and not very often - a camera - mostly I've got one eye on a tree with a camera and am ready to get up it!!