San Diego, California
been visiting the distant cousins this summer—the very distant ones,
the apes with whom we shared a common ancestor between 18 and 7
million years ago. While I'd prefer to visit them in the wild, in
southeast Asia and central Africa, I had to settle for an intense
dose of them at the San Diego Zoo's excellent habitats. I arranged
for a behind-the-scenes visit with their keepers for a dozen
scientists interested in human evolution, who wanted to know more
about what ape behaviors were like.
evolved from the monkeys about 25 million years ago; they lost their
tails in favor of doubling brain size. The gibbons and siamangs are
on a branch that dates back about 18 million years, and the orangs
on the branch at about 12 million years. They are the acrobats of
the apes, with shoulders far more versatile than monkeys. The
siamangs and the orangs are housed together at the San Diego Zoo and
it makes for a fascinating display of virtuosity. I made good use of
my new telephoto lens, as you'll see when the book comes out next
spring; the postcard pictures are of the siamang, an orang, and
gorillas split off about 8-10 million years ago. They sure lost the
acrobatic skills of their presumed ancestor with the orangs, perhaps
because they specialized in a vegetarian niche of low quality food
that requires a very long gut and big belly.
million years ago, we last shared a common ancestor with the chimps
and bonobos. The hominids differed, initially, in losing the big
canine teeth and in standing upright enough to rearrange the hips.
They had a pint-sized brain like the other great apes; the tripling
of brain size didn't even begin until the ice ages kicked in about
2-3 million years ago. If only more of those intermediate species
had survived—both Neanderthals and, in China, Homo erectus went
extinct recently, after our own lineage achieved structured thought,
our capacity for long sentences and contingent planning.
any of the four great ape species will, to an extent unmatched by
the lesser apes and the monkeys, remind you of people that you know.
The chimps and bonobos are considerably more social than gorillas
(what with their harem structure that excludes most males) and the
orangs (who, as adults in the wild, seldom see one another except
for "conjugal visits"). Watching bonobos (essentially the oldest of
the chimp subspecies, from the left bank of the Congo), you will see
reassuring touches, the arm around the shoulder, kissing, and the
grinning "play face."
This overlap with what we had supposed were exclusively human
behaviors was one of the surprises of the last few decades of
research. Judging from the chimps and bonobos, a lot was in place
before the hominid branch split off at 7 million years ago, perhaps
even the capacity for simple language (with
of tutoring, they can do about as well as two-year-old kids at
understanding a sentence). They may lack structured thought, but so
might our big-brained ancestors—at least, until about 50,000 years
ago when sustained creativity first appears in the archaeological
record. Before then, Homo sapiens wasn't doing much that was any
different from the Neanderthals. Conservatism was the rule, not
innovation, and the life of the mind was probably rather minimal.
That's why the great apes are so precious to us. Along with the
stones and bones of archaeology, these distant cousins are the other
small window into our own past. Take your binoculars, to watch those
fleeting facial expressions, and try to match them up with people