Water’s
Ancestors
By Bruce Bower
Edge
In a cave hugging South Africa’s lush southern coastline, Curtis Marean suspects he has cornered a wily Stone Age crewthat brought
humans back from extinction’s brink.
These plucky refugees of continent-wide desolation were able to pull off such
a stunning evolutionary turnaround
because they got lucky. A coastal oasis
near the bottom of the world spread its
sheltering arms in the nick of time.
Marean proposes that it was there,
where the Arizona State University
archaeologist now conducts excavations,
that humankind’s mental tide turned
sometime between 164,000 and 120,000
years ago. Seaside survivors learned
to read the moon’s phases in order to
harvest heaps of shellfish — brain food
extraordinaire — during a few precious
