Review: Not a chimp: The hunt to find the genes that make us human

From ANIMAL PEOPLE, November/December 2010:

Not a chimp: The hunt to find the genes that make us human
by Jeremy Taylor
Oxford University Press (c/o 198 Madison Ave., New York, NY 10016),
2010. 338 pages, paperback. $14.95

This first book by Jeremy Taylor, for 30 years a scientific
documentary film maker, is intense. Not a chimp: The hunt to find
the genes that make us human consists chiefly of discussions of such
topics as sequence divergence, pyramidal neurons, and translocation
of chromosomes. Taylor is aware of the implications of his research
for animal rights activists, philosophers, and attorneys, and for
species conservationists, bioethicists, and biomedical researchers
too, but he limits his discussion of these matters to a few pages at
the beginning and end of what is otherwise a scientific treatise.

Indeed, Taylor seems to have little interest in the
application of any of the scientific findings he brings together
relevant to the question as to what distinguishes humans from
chimpanzees and other apes. Taylor opines at several points that he
believes neither animal rights arguments nor conservation of great
apes are well-served by arguments which assert that chimps and other
great apes should be protected because they are so much like us, but
he does not go into detail. What concerns Taylor is that the case
for humans as a subspecies of chimp is in his view ill-founded–and
he makes a very strong scientific case in that direction.
First, Taylor points out, that humans and chimps apparently
branched off from a common ancestor six million years ago does not
mean that we are separated by only six million years of evolution.
Rather, we are separated by 12 million years of evolution: the
distance each species has evolved since our ancestors diverged.
Second, the difference of a mere 1.6% in the content of
chimp and human DNA does not really mean that all the differences
between us are accounted for in that 1.6%–or that we are as closely
related to a banana as the possession of 50% of our genes in common
with a banana would imply. As Taylor explains in detail, the
content of a gene is much less important in species differentiation
than the order of gene expression. A convenient metaphor for that is
the 26 letters in the alphabet. The same 26 letters and the sounds
that they make appear in any sentence written in the English
language, or any vocalization. The meaning they convey, however,
varies hugely depending on how they are ordered and at what length.
Of further importance is the role of the genes that differ
between human and ape. Apparently a disproportionately large number
of these genes are the controllers that direct what the other genes
will do.
Taylor briefly reviews the evolution of the notion that
chimps are quasi-humans, including the work of Jane Goodall, who
long lived among among wild chimps in Tanzania. Goodall established
that many traits once thought to be exclusively human, including
some capacity for abstract reasoning, are found in chimps. Most
influentially, Goodall witnessed and reported the first examples of
chimps using tools. In 1960 she saw chimps use grass stems to fish
for termites “licking off the insects that clung to the probe,”
Taylor recounts. Later Goodall and other observers saw chimps using
sticks to “dip for honey and probe for bees.”
But limited capacity for abstract reasoning has since 1960
been discovered in dozens of other species. Tool use has been
discovered in hundreds, including arthropods (spiders) and
cephalopods, an ancient branch from the mollusk family. Such
“human-like” traits, though often well-known in folklore,
apparently had not been scientifically observed and documented
earlier only because no one was looking for them–and though
discovering these traits helps to establish that animal intellect has
long been underestimated, and to establish human kinship with
animals, this discovery does not lessen the reality that we have
developed our intellectual capabilities far beyond those of any other
animal.
Chimps are undoubtedly smart. They can learn to play some
computer games better than humans, and play complex tricks on each
other. But they are not human. They do not speak our language
fluently, though a few have learned some basic language skills.
Neither to they have the human ability to exercise complex abstract
reasoning. Despite the intelligence of chimps, they are more like
other animals in their behavior, when left in their own habitat,
than like humans, who typically begin modifying any habitat we
occupy.
“They aren’t us,” summarizes Taylor, describing some of the
disasters that have befallen people who have tried to raise chimps as
quasi-children–notably St. James and LaDonna Davis, who kept a
chimp named Moe as their son.
Eventually, after Moe injured two visitors in separate
incidents, he was placed in a sanctuary, by court order. In March
2005 St. James and LaDonna Davis visited Moe to celebrate his 39th
birthday with new toys and a raspberry sheet cake. Several resident
chimps from adjoining cages escaped and attacked St. James, causing
him some of the most severe facial injuries that a human has ever
survived. His testicles and a foot were severed.
Taylor does not deny that chimps are much more human-like,
in anatomy and behavior, than most other animals. He does not argue
in any way that chimps should be exploited or mistreated. But he
does point out that even the most widely divergent frog species are
actually more closely related than human and chimp, when gene
expression is properly taken into account.
“The philosopher Peter Singer argued that when we put human
interests above the interests of any other species, we are guilty of
speciesism–a form of racism,” Taylor summarizes. “When scientists
like Jane Goodall agree to stand as expert witnesses in favor of
human rights for Hiasl Pan,” the chimp who was subject of a failed
lawsuit seeking human rights for chimps in Austria, “are they not
unwittingly guilty of a similar type of mild racism because, by
stressing the continuity between us and chimps, they make way for
chimpanzees to join a club which always puts its interests first?
Instead of spreading continuity,” Taylor argues, “they are simply
broadening this species chauvinism.”
Concludes Taylor, “Re-branding chimpanzees as humans will
not save them from extinction. Rather, it behooves us as humans,
to find ways of managing our affairs that are far less ruthless and
dismissive of the survival of the rest of the animal kingdom, and
the environment on which they depend.”
–Debra J. White