i listened to an antique flute in an music healing workshop i've been last year.
all the instruments, all the drums are fallowing the heart rhythm, the ancestral beat for calling people in.

i don't agree with your last part. although i don't have an musical background, but i think that they did have real fears of being hunted by other animals. they were not just walking alone in the wild carefree. there sounds were designed to fight, to attack, like a signal they made to predate or defense.

looking forward for your next post :) i like your subjects :))