Complex sentence: Scholars cannot interpret the pictograms, and do not know for certain what meaning the animal reliefs had for visitors to the site; the variety of fauna depicted, from lions and boars to birds and insects, makes any single explanation problematic.
Split into simpler sentences: Scholars cannot interpret the pictograms, and do not know for certain what meaning the animal reliefs had for visitors to the site. The variety of fauna depicted, from lions and boars to birds and insects, makes any single explanation problematic.