William H. Calvin, A Brain for All Seasons: Human Evolution and Abrupt Climate Change (University of Chicago Press, 2002). See also http://WilliamCalvin.com/BrainForAllSeasons/Cape.htm.
ISBN 0-226-09201-1 (cloth) GN21.xxx0
Available from amazon.com or University of Chicago Press.
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William H. Calvin
University of Washington
of pumping, tides must be the original stroke-after-stroke device.
Tidal fish traps show you how our ancestors could have gone
fishing along this coastline, even without spears or fish hooks.
If the tide flushes into a gully, all they had to do is to pile
up some boulders to half the height of high tide, making a sill across
the gully entrance. It
doesn’t have to hold back the water effectively, only the larger fish
that aren’t quick enough to notice the falling tide.
Now the pump has a fallback.
And so some fish will remain behind the dam, high and drying,
there for the taking on your daily visit.
While the evidence for such things along the southern coastline
probably doesn’t go back more than several thousand years to when the
pastoralists arrived, this is the sort of thing that even bipedal apes
might have been able to do. There
are many natural examples, called tide pools, that trap small fish and
crabs every day. These
could have served as examples and indeed you can block up the low
points of natural tide pools to enlarge them, giving you the idea for
how to approach the problem on the larger scale of a little inlet.
One can easily imagine people piling up rocks to fill in the low
points of the entrance. Groups
would have zealously guarded the good gullies, perhaps even settling
down for a while.
The cold current keeps the ocean here about 11°C, in
contrast to the 20°C waters east of Cape Agulhas.
And so the modern version of the fish trap is the tidal swimming
pool, sometimes seen in the beaches of the western Cape Town suburbs.
A particularly high tide flushes out the shallow pool with new
water every two weeks. The
sun then warms up the trapped water enough for you to swim comfortably. And maybe you’ll encounter a fish, too, looking for a way
out. It’s too bad that
there isn’t some way for the tides to pump the water higher and
higher with each tidal extreme, with a ratchet tracking it up.
You have to wait for biological evolution before such ratchets
There are a series of caves facing out onto the Indian Ocean
east of here, such as Nelson’s Bay Cave and Klasies River.
Klasies is particularly important, as it has remains of
anatomically-modern (except for chins) Homo sapiens from before
100,000 years ago, back into the last major warm period.
Its tools are the usual Middle Stone Age types, and the bones
include a lot of eland and penguins, together with some Cape buffalo
and wild pigs. Nelson’s
Bay Cave, a deep cave somewhat above the high-water line which we
explored several days ago, has layers from the last ice age and into
our present warm period; their tools included projectile weapons, and,
judging from the bones they discarded, they had gotten good at bringing
home the bacon and dealing with the ill-tempered Cape buffs, among the
most dangerous animals in Africa.
southwest corner of Africa is about as far south of the equator
as Los Angeles is to the north of the equator.
However, L.A. doesn’t have ostrich wandering the bush or
shoreline-patrolling baboons snatching your unguarded picnic basket.
Indeed, this place looks like a high mountain plateau, treeless
with heathers and high winds. You expect to feel breathless due to the
thin air but it is located at sea level.
The lighthouse is on another point just a kilometer east, Cape
Point, which is much higher and looks down on the Cape of Good Hope. The ocean stretches west to Argentina and south to
Dias reached here in 1488 in the intrepid Portuguese caravels inspired
by Prince Henry the Navigator. John
II of Portugal named the cape Cabo da Bõa Esperança,
Portuguese for Cape of Good Hope (the “hope” refers to trade
prospects with China), when his explorers returned and presented their
That the Cape of Good Hope wasn’t named something else sixty
years earlier by a Chinese admiral, Zheng He, is one of the major
ironies of history. The
Cape is not, by a half degree, the southernmost extent of Africa
(that’s Cape Agulhas farther east, where the ocean’s name
officially changes from Indian to Atlantic.
Agulhas would not have impressed a sailor very much, being just
another protrusion of a wandering shoreline, important only in
retrospect while tabulating latitudes.
But when you round the Cape of Good Hope going west, the water
turns cold, kelp beds line the shore, and the sea coast stretches away
to the north, seemingly forever. You
know that you’ve turned a corner.
The Chinese sailors would have wondered where it led, and might
have gone on to discover Europe. But
it appears that they didn’t make it quite this far.
Between 1405 and 1433, so-called “treasure fleets” sailed from China to explore India and the East African coast. The scale of the venture, hundreds of ships at a time, makes European exploration pale by comparison. The Portuguese, later that same century, were far less ambitious than the Chinese but they succeeded. Three ships, led by Vasco da Gama, eventually rounded this cape in 1497 and then continued on to India in 1498.
So why didn’t the Chinese discover Europe, and beat the
Europeans to the Americas and Australia?
explorations were suspended before their ships ever turned the corner
into the Atlantic Ocean. Back
home, power shifted to a traditionalist faction that wanted to distance
China from the outside world. The
eunuchs in the government who supported exploration fell into disfavor.
By a century later, the act of venturing abroad in a multimasted
ship, even to trade, had become a criminal offense in China.
They even abolished mechanical clocks after leading the world in
clock construction technology.
For an equivalent, you have to imagine an ultraconservative
takeover of the U.S. that, for some reason, frowned on both airplanes
and computers, with Seattle and Silicon Valley in deep depression and
the conservative radio talk show hosts beginning to look liberal in
comparison to the people in power.
The short-sighted in China set the stage for Europe’s 400-year
domination of coastal Asia, when it might have been vice versa.
As Jared Diamond is fond of pointing out, various European
countries did equally stupid things but, since Europe was never
politically unified in the way that China was, there was always some
European country to keep exploring when others stagnated.
As the story of Christopher Columbus shows, sometimes an Italian
explorer unable to find financial support back home could even persuade
a Spanish king (probably competing with the Portuguese) to bankroll an
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