This article talks about the use of horse skulls to improve acoustics. Okay, that's a practical component. But you notice that the cultures doing this are very fond of horses. There's definitely a ritualistic aspect. Because if there wasn't -- if the horse wasn't special -- then we'd see a variety of different skulls and probably other objects as well. This is supported by separate finds regarding horse heads and horses in other finds of mystical significance in the same areas.