the markings are kinda crude representations of what was killed. A bit like hieroglyphs Best seen in the xeno and hound glyphs. Undoubtedly there are many many more "kill glyphs" Wolf's bio is covered in glyphs, it would be fair to assume each one represents a kill of some kind. Also some may represent trial completions, Had Scar survived the "Kainde Amedha Chiva" or hard meat (xeno) trial he would have, most likely due to their tribal nature, been branded with a glyph to show this by the Elder.