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/Baringo.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
looking northwest from the shores of Lake Baringo toward the Tugen
Hills. They have long been
thought to be a good place to look for missing links, as their layers
go from about 250,000 years old down to about 14 million years old.
In a deep ravine near Kapsomin, about 50 km from here, a
French-Kenyan paleoanthro team is excavating the five earliest-known
hominid individuals. The
nearby volcanic layers seem to date them back to the Late Miocene,
about 6 million years ago.
It will be years yet before the paleoanthropology community
agrees on how to place them, together with the new finds in the Middle
Awash region of Ethiopia at 5.8 million; both early hominids appear to
have lived in relatively wet woodlands.
Those dates are right about when the DNA dating suggests we last
shared a common ancestor with the chimp-bonobo branch.
“Millennium Man” is upright but it still shows signs
(paleoanthropologists love to talk about curved bones) of apelike
specializations for life in the trees.
Ron Clarke’s new Sterkfontein “Stw573” skeleton at 3.3
million years ago still has feet that can grab a tree branch, along
with its weight-bearing heel bone.
So real efficiency in bipedal stride may have taken over three
million years to develop after upright stance did – maybe even as
long as it took brains to finally start enlarging at 2.4 million years
Doing paleoanthropology is much like doing a jigsaw puzzle
without a picture of the pattern – and where you have to dig to
discover the pieces! And
then the pieces are worn and broken, making them ambiguous, able to fit
into several different places in your imagined pattern.
You guess at the pattern, using information from elsewhere in
evolutionary biology and paleontology as a guide, but the general
guiding principles such as Darwinism and analogies from development are
very broad, leaving lots of room for sheer happenstance.
Human evolution from an apelike ancestor only happened once, and
the general principles merely tell you something about what the average
result might be if you ran the experiment a hundred times.
And so paleoanthropologists have to guess a lot.
This makes for lively controversies.
Reading a historical account of paleoanthro (try Ian
Tattersall’s The Fossil Trail or Alan Walker and Pat
Shipman’s The Wisdom of the Bones) shows you how the current
ideas have been built up. The
track record shows you how likely it is that the current ideas are also
missing a few important things.
Walking back from dinner in the dark, fully bipedal, we ran into
the hotel’s uniformed askari. My
cousin asked him in Swahili if hippos really came up on the lawn
outside our front doors. Oh
yes, the guard said, pulling out his flashlight, and he led us down the
path past our cabins – and there in the dim light were two full-sized
hippos, mowing the grass.
They come up all through the night in different groups,
sometimes a half-dozen at a time.
So you sleep fitfully under your mosquito netting, listening for
exaggerated treble and bass sounds, for malarial buzzing inside the
room and for two-ton munching sounds just outside.
At least no troop of baboons bounced on my roof for half the
took a nice hour-long boat ride in the early morning light and
saw hippos chasing one another, crocs beginning to sun themselves on
shore, herons hopefully inspecting the shallows, some cormorants diving
farther offshore. Besides
all the colorful small birds (weavers are very common here), there were
hornbills, Marabou storks, and fish eagles.
People were coming down to the lake edge to haul water, wash
clothes, and fish. We saw
the little one-person boat of lashed-together firewood called a
coracle, about the size of a floating lawn chair.
the tidal fish trap, it doesn’t hold water, but the sticks keep the
fisherman afloat. His
catch is kept in the bottom of the boat and benefits from the constant
change of water. The fisherman paddles with split shells, one in each hand.
Close inshore (where it’s shallow enough to wade ashore), and
at the flat water of dawn, this technique is just fine.
It provides an interesting view of how boats might have gotten
started and become valued.
Then after breakfast, we looked up to see a camel working over
the local trees. Perhaps,
I said speculatively, some camels have been driven south from Lake
Turkana by the current dry spell.
Around here it has been raining on and off for the last week, so
we are seeing desert-bloom conditions.
We almost stumbled over a medium-large tortoise crossing the
grass to browse on the well-watered bushes.
The hotels don’t have to bait the premises to get animals to
come visit the tourists. All they have to do is to water the plants and wait.
the cousin, who is busy finishing up a book manuscript, and I
were sitting in the shade, keeping an eye on the camel and the hippos
from our lawn chairs, each nursing the battery life in a laptop
computer while trying to get some work done.
We kept hearing this faint bugle-like noise.
It sounded somewhat like one of those miscellaneous computer
vocalizations. But it
stopped after several repetitions.
I’d already been fooled by a bird that sounded like a truck
back-up warning horn, and another that sounded like a telephone.
I was perfectly willing to believe in a bird-call that
duplicated a computer sound, just like those starlings in Copenhagen
that imitate cell-phone rings and perplex the pedestrians.
A half-hour later, we heard that bugle sound again. And again. We
kept commenting on it, speculating about bird mimicry, and going back
Then a window popped open on my computer screen. It contained the name of the cousin’s computer, not mine. Realization dawned. The infra-red ports on the two laptops had discovered each other, had exchanged names, and had been repeatedly announcing the fact. I’m sure no one else at Baringo (and certainly not the camel) understood why we laughed uproariously for minutes, at the absurdity of it all happening in this particular setting.
After lunch, we saw a fish eagle and two crested cranes near the
dock. That’s when the
camel came over to us, looking for a handout.
If a camel could ever be said to have an ingratiating smile –
well, no, I suppose this one just looked opportunistic.
So it is likely an experienced local camel, well versed in the
ways of tourists, not a recent refugee from the wilds of Turkana.
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