In the Bradshaw website they analyze how the paintings go from cherry color (ochre) to purple. 

The bacteria can either destroy what they come in contact with or preserve it into eternity.

How and what makes the choice?

How did the ancient artists know that pigment was alive?

Perhaps through hundreds of years of observation and transmission of oral knowledge.

Ochre itself was deemed a connector to the energy of the universe.  It wasn't just symbolic, it was an actual mechanism, a dynamic living bridge...

The paintings go back as far as 70,000 years and are figurative, depicting women dancing. 

Women artists probably created them.