Archeologists Discover 'Brain Food' in Early Human Ancestors' Diet

/PRNewswire/ -- A team of scientists now know what may have helped fuel the evolution of the human brain two million years ago. Archeologists working in Kenya unearthed evidence that our human ancestors ate a wide variety of animals including fish, turtles and even crocodiles. Based on analyses of animal bones and stone tools they excavated, the research team found that our early ancestors incorporated aquatic "brain food" in their diet.

"These aquatic foods are really important sources of the long-chain polyunsaturated fatty acids and docosahexaenoic acid that are so critical to human brain growth," said co-author and paleoanthropologist Dr. Richmond. "Finding these foods in the diets of our early ancestors suggests they may have helped to lift constraints on brain size and fuel the evolution of a larger brain."

The discovery of such a diverse animal diet is important because early human brain size increased dramatically after two million years ago. Growing a large brain requires an enormous investment in calories and nutrients and places considerable costs on the mother and developing infant. Anthropologists have long considered meat in the diet as key to the evolution of a larger brain. However, until now, there was no evidence that human ancestors this long ago had incorporated into their diets animal foods, from lakes and rivers, rich in brain nutrients.

A team of scientists from Kenya, the United States, the U.K., Australia and South Africa discovered a 1.95 million year-old site in northwestern Kenya in 2004. Preservation of the excavated site was so remarkable that the team was able to develop a detailed reconstruction of the environment. Over four years, the scientists excavated literally thousands of fossilized bones and stone tools, and were able to determine that at least 10 individual animals, and perhaps many more, were butchered by early humans at this site. Many of these bones showed evidence of cut marks made by early human ancestors as a result of using sharp stone tools to cut meat from the bones or crush long bones to access the fat-rich bone marrow.

"At sites of this age we often consider ourselves lucky if we find any bone associated with stone tools, but here we found everything from small bird bones to hippopotamus leg bones," said archeologist David Braun of the University of Cape Town in South Africa, who was the lead author on the research.

Gaining access to smaller animals like turtles and fish may have allowed these early humans to increase the protein in their diet without the danger of interacting with dangerous carnivores, such as lions and hyenas. These early humans were relatively small and not well suited to compete with the large carnivores that lived at that time. Stumbling upon brain-fueling food may have been a fortunate side effect of finding foods at lakes and rivers.

The research was funded by the National Science Foundation. The project was directed by Jack Harris of Rutgers University and represents a collaborative effort between National Museums of Kenya and a host of international institutions. Paleontologist Marion Bamford of the University of Witswatersrand in South Africa identified fossilized plant remains that revealed the wet and possibly marshy environment in which these early humans were living. Lead zooarchaeologist Jack McCoy of Rutgers University identified bones of various animals including turtles, fish, crocodiles and large antelopes that ended up as the meals of these early humans. Dr. Richmond of GW took part in fossil identification and analyzing how the findings were important for human evolution.

The site, known to the archaeologists by the moniker FwJj 20, is located in the northern part of the Koobi Fora research area on the eastern side of Lake Turkana in Marsabit District, Kenya. The presence of overlying layers of volcanic ash helped the team pin down the age of the site. Geologists on the team, Naomi Levin of Johns Hopkins University and Andrew Herries of the University of New South Wales, Australia, were able to use a combination of techniques to estimate the age of the site as close to 1.95 million years. David Braun and his international team will return to northern Kenya to find more answers to questions about the diets of our earliest ancestors.

The article, "Early hominin diet included diverse terrestrial and aquatic animals 1.95 Ma in East Turkana, Kenya," will appear in the May 31, 2010, issue of Proceedings of the National Academy of Sciences (PNAS). PNAS is a weekly journal that publishes cutting-edge research that spans the biological, physical, and social sciences.

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The George Washington University was created by an Act of Congress in 1821. Today, GW is the largest institution of higher education in the District of Columbia and has additional programs in Virginia. The University offers comprehensive programs of undergraduate and graduate liberal arts study, as well as degree programs in medicine, public health, law, engineering, education, business and international affairs. Each year, GW enrolls a diverse population of undergraduate, graduate and professional students from all 50 states, the District of Columbia, and more than 130 countries.

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Scientists Announce the Discovery of a 47-Million-Year-Old Primate Fossil that is Set to Revolutionize Our Understanding of Human Evolution

/PRNewswire/ -- Scientists have announced today the discovery of a 47-million-year-old human ancestor. Discovered in the Messel Pit, Germany, the fossil is twenty times older than most fossils that explain human evolution. Known as "Ida," the fossil is a transitional species, showing characteristics of the very primitive nonhuman evolutionary line (prosimians, such as lemurs), but even more closely those of the human evolutionary line (anthropoids, such as monkeys, apes, and humans). This places Ida at the very root of anthropoid evolution -- when primates were first developing the features that would evolve into our own. The scientists' findings are published today by PLoS One, the open-access journal of the Public Library of Science.

Little, Brown and Company, a division of Hachette Book Group, will publish THE LINK, by Colin Tudge, on Wednesday, May 20, 2009. The book will reveal in full detail the entire story of the discovery, excavation, and preservation, and the revolutionary significance of Ida. THE LINK begins with a foreword by Norwegian fossil scientist Dr. Jorn Hurum of the University of Oslo's Natural History Museum, who for the past two years has led an international team of scientists as they secretly conducted a detailed forensic analysis of the extraordinary fossil, studying the data to decode humankind's ancient origins. At 95 percent complete, Ida is set to revolutionize our understanding of human evolution.

Unlike Lucy and other famous primate fossils found in Africa's Cradle of Mankind, Ida is a European fossil, preserved in Germany's Messel Pit, a mile-wide crater whose oil-rich shale is a significant site for fossils of the Eocene Epoch. Fossil analysis reveals that the prehistoric primate was a young female. Opposable big toes and nails rather than claws confirm that the fossil is a primate, and the presence of a talus bone in the foot links Ida directly to humans.

The fossil also features the complete soft body outline as well as the gut contents. A herbivore, Ida feasted on fruits, seeds, and leaves. X-rays reveal both baby and adult teeth, and the lack of a "toothcomb," which is an attribute of lemurs. The scientists estimate Ida's age when she died to be approximately nine months, and she measured approximately two feet in length.

-- Ida lived 47 million years ago, at a critical period in the Earth's
history. Her life fell within the Eocene Epoch, a time when the
blueprints for modern mammals were being established. After dinosaurs
became extinct, early horses, bats, whales, and many other creatures,
including the first primates, thrived on a subtropical planet. The
Earth was just beginning to take the shape that we know and recognize
today -- the Himalayas were being formed and modern flora and fauna
were evolving. Land mammals, including primates, lived amid vast
jungles.

-- Ida was found to be lacking two of the key anatomical features found
in lemurs: a grooming claw on the second digit of the foot, and a
fused row of teeth in the middle of her lower jaw, known as a
toothcomb. She has nails rather than the claws typical of
nonanthropoid primates such as lemurs, and her teeth are similar to
those of monkeys. Her forward-facing eyes are like ours -- which would
have enabled her fields of vision to overlap, allowing 3-D vision and
an ability to judge distance.

-- The fossil's hands show a humanlike opposable thumb. Like all
primates, Ida has five fingers on each hand. Her opposable thumb would
have provided a precision grip. In Ida's case, this would have been
useful for climbing and gathering fruit; in our case, it allows
important human functions such as making tools and writing. Ida also
would have had flexible arms, which would have allowed her to use both
hands for any task that cannot be done with one -- like grabbing a
piece of fruit.

-- Evidence of a talus bone links Ida to us. The bone has the same shape
as it does in humans today, though the human talus is obviously
bigger. Extensive X-rays, CT scanning, and computer tomography reveal
Ida to have been about nine months old when she died and provide clues
to her diet, which included berries and plants. Furthermore, the lack
of a bacculum (penis bone) means that the fossil was definitely
female.

-- X-rays reveal that a broken wrist may have contributed to Ida's death
-- her left wrist was healing from a bad fracture. The scientists
believe she was overcome by carbon dioxide gas while she was drinking
from the Messel Lake; the still waters of the lake were often covered
with a low-lying blanket of the gas as a result of the volcanic forces
that formed the lake and were still active. Hampered by her broken
wrist, Ida slipped into unconsciousness, was washed into the lake, and
sank to the bottom, where the unique conditions preserved her for 47
million years.

THE LINK will be published in the United Kingdom by Little, Brown, in Germany by Piper Verlag, and in France by JC Lattes. The findings of the two-year study will also be revealed by Atlantic Productions in a special documentary film, The Link, to be screened by History on Monday May 25, 2009, at 9:00 p.m. EDT/PDT, and broadcast worldwide in over twenty countries.

An interactive, content-rich website about Ida has been launched at www.revealingthelink.com.

The full scientific findings from the study are set out in the paper "Complete primate skeleton from the middle Eocene of Messel in Germany: morphology and paleobiology," published by PLoS One, the Public Library of Science's interactive open-access journal for the communication of peer-reviewed scientific and medical research (www.plosone.org).

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