Hello,

Someone pointed out this article in the January 15th edition of the San
Diego Union-Tribune to me.

It makes a strong argument against a fruitarian diet IMO.

mark

Page A-10
Paul Recer
ASSOCIATED PRESS
15-Jan-1999 Friday
WASHINGTON -- The ancestors of modern humans were more than
tree-climbing
plant-eaters, according to a new study. The ape-like creatures millions
of
years ago probably also caught and ate small animals -- even before the
invention of stone tools.
Researchers who studied tooth enamel from the fossilized remains of
hominids called Australopithecus africanus found the chemical signature
of
foods that grew on the open plains of South Africa, as well as in the
forest.
This means that "africanus was not just a tree dweller," said Matt
Sponheimer, a researcher at Rutgers University in New Brunswick, N.J.
"Our study shows that this early human ancestor found its food both in
the
forest and in the open areas," said Sponheimer, co-author of a study
appearing today in the journal Science.
Earlier studies, based on bones in the jaw, arms, hands and feet, had
suggested the species subsisted only on leaves and fruits plucked from
forests -- rather like the diet of present-day chimpanzees, the nearest
animal relative to modern humans.
But Sponheimer said the tooth chemistry study proves the species had a
much
more varied diet.
For some, up to 25 percent of their diet came from grass or grass-eating
animals, said Sponheimer. "For one specimen, it was 50 percent."
The study makes clear the early hominids were eating something different
from what researchers had assumed, said John Kingston, a Yale University
expert on early human-like species.
"Among the things they could have been eating is meat, which is a
fascinating possibility," Kingston said.
But the study didn't conclusively determine if the species ate meat from
grass-eating animals or merely the seeds and roots of grassland plants,
which would give the same tooth-enamel signature, Kingston said.
Fossils of the species have been found only in South Africa. It lived 2
million to 3 million years ago and resembles Lucy, the famed, nearly
complete hominid skeleton found in Ethiopia in North Africa. Lucy,
however,
is slightly more ape-like and is identified as A. afarensis, an earlier
human ancestral species.
Africanus was not much bigger than a chimpanzee, at about 4 feet and 90
pounds, but had a slightly larger brain. It walked on its hind legs, but
some specimens suggest an opposing big toe rather like a tree-climbing
ape,
said Sponheimer.
This feature, along with teeth that resemble those of apes, have led
other
researchers to conclude the species lived in the trees and ate only
plants.
In their study, Sponheimer and co-author Julia A. Lee-Thorp of the
University of Cape Town in South Africa extracted tiny bits of tooth
enamel
from the specimens and then analyzed the carbon isotope ratios.
Isotopes are atoms of the same element that have a different number of
neutrons. For instance, trees and bushes contain more carbon-13 than do
grasses that grow in open areas. The isotopic ratios in the enamel
reflect
which of these plants the animals ate. Meat-eaters acquire the isotopic
signatures of their prey.
"In effect," said Sponheimer, "you are what you eat."
For this reason, if the species ate animals that fed on grasses, their
tooth enamel would show the carbon-13 signature of grassland plants, he
said.
The specimens analyzed had carbon-13 signatures between that of forest
animals and plains-dwelling grass-eaters.
That indicates the species ate foods from both the forests and the
plains.
It also suggests they fed on high-protein animal foods, perhaps insects
or
small mammals, that lived on grasses.
There's no evidence the species had stone tools, but it is possible the
hominid killed small game with rocks or used twigs to gather insects, a
technique observed among chimpanzees grazing on termites, Sponheimer
said.
Hominids that appeared later, such as Homo habilis, used stone weapons
to
kill larger mammals. It is thought this higher-protein food may have
played
a role in the evolution of the larger brain of modern humans.