Oldest Skeleton in Human Family Tree Surprises ...(close to four-feet tall were first disco...),Health

It has taken 17 years for scientists to piece together a portrait of Ardi's life and times.

Ardi has smaller canines than chimps, was able to walk on two feet on the ground and, thanks to a "grasping big toe," could also travel easily in trees. Her limbs and hands more closely resembled those of now-extinct apes.

And the fragments of Ardi's skeleton had remained in the same place for 4.4 million years. "Where the animal fell to the ground was where it got buried," said Hlusko. "The animal and plant material stayed exactly where it fell, which is just amazing."

This enabled Giday WoldeGabriel, another author on the papers and a geologist with Los Alamos National Laboratory in New Mexico, to accurately (give or take 60,000 or 80,000 years) pinpoint a date using three different methodologies.

"We made sure they hadn't been moved or mixed with something else," said WoldeGabriel, who is originally from Ethiopia.

Researchers were also able to reconstruct Ardi's environment to a degree not possible for Lucy, because bits and pieces of her history had long been washed away or moved.

Ardi lived in a forested area with grasslands possibly several miles away. This detail challenges one school of thought which holds that bipedalism came about as a response to living in grasslands.

Scientists also found thousands of specimens from small mammals in the area, along with indications of fig trees, birds (including owls and parrots) and larger mammals such as elephants and giraffes.

Ardi is not the last common ancestor but she is "tantalizingly close," Laitman said.

"It's showing us that if you went even earlier and found the Great E
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