Humans playing dressup — its analogous to the wearing of masks in Greek, Roman, and other ancient cult rites.
Dress up? OK, I’ll accept that as an idea for a mask, similar to the Kachina masks, but why are the drawings of the human figures so disproportionate physically when the animals aren’t? It just makes no sense to draw something so different from the normal human physique.
You’d have to posit that the dress up includes using stilts under long robes to give that long torso and thin legs.
Or I suppose it could be different artists, one with skills and one without.