They may serve the same purpose as ship silhouettes.....................
I tend to agree.
It is best if those who are charged with defending their people from an enemy can discern friend from foe at the greatest possible distance.
And the hunters of a tribe were also that tribe’s defenders.
It’s probably best not to take any of my theories on pre-history too seriously, though.
After all, I believe cannabis was responsible for the beginnings of civilization.
Who would think to plant food in fields right near where they lived and gather up baby animals to pen up for quick food other than a bunch of lazy arsed stoners who had to deal with the overwhelming need for munchies on a regular basis?