The level of sophistication in the cave artifacts show these were highly bred Whites. The slings they had used a method of weaving that would be a good exercise for people to try and recreate. The Egyptians make slings as pretty but needed an apparatus to weave them on while those from this cave could be done just with hands.That is how I heard about this
http://www.woodcraftwanderings.org/hunting.html
Also the Duck lures are one of the most amazing artifacts from White history.
I am sure Whites selectively breeding for height could produce such average heights in a few generations.