FORT COLLINS--A day's work for Colorado State anthropologistDiane Waddle can include encounters with deadly cobras,excavations on steep walls using rock-climbing equipment andtraveling to fossil sites on roads so rough a kidney belt isrequired.
But the treacherous conditions are worth the bounty Waddleand two other anthropologists recently uncovered in a remotelimestone cave in Botswana, Africa: fossilized bones of thousandsof tiny bats, shrews, birds and frogs as well as a complete skullof an adult primate and the jawbone of a juvenile primatebelieved to be ancient ancestors of present-day baboons.
The vast collection of fossils is one of the few uncoveredin Botswana and contains well-preserved specimens of smallmammals that may have roamed the earth sometime between 100,000and 3 million years ago. Most likely used by owls and othermammals to eat their prey, the cave is so rich with fossils it'scalled Bone Cave.
Waddle and the other researchers believe the find can helpfill the gap in the fossil record of Botswana, an area that hasnot been a major focus for anthropologists or archaeologists inrecent years. Although there are numerous sites containing stonetools in Botswana, the only human or primate remains fromBotswana are less than 10,000 years old and are fully modern.Other fossils found in Botswana have been from the Middle StoneAge, roughly 100,000 years and earlier.
"This is a great find because of the wealth of fossils inthe cave," Waddle said. "It's particularly important becauseBotswana has virtually no fossil sites of this kind and therereally is no fossil record of primates at all. Many fossil sitesmay only produce a few fossils.
"This is really impressive because it's like a big pile ofbones glued together."
Waddle said the main reason that not much is known about theevolutionary history of this region is the remote location of thecaves; about an 11-hour drive from the nearest town. To get toBone Cave, the research team must rely on tire tracks from theprevious year's expedition, which often proves difficult. Therainy season causes grasses to grow over the tracks and elephantsscar the road with footprints.
Using a grant from the National Geographic Society, Waddlebegan making the trips to Bone Cave with anthropologists CallumRoss of SUNY Stoney Brook University and Blythe Williams of DukeUniversity in 1994. Colorado State anthropology students JodiLaumer and Lawrence Steumke traveled to Africa with the team onthe most recent trip.
In the project's first two years, researchers took aninventory of the cave and learned how to better navigate itsnarrow passages, which serve as a link between two chambers wherethe fossils are located. To get to the main chamber--called theDrop Room--the research team must climb down a steep rubble slopeto a small opening measuring 4 feet across. The larger primatebones are embedded in the steep rock walls and ceilings of theDrop Room, making the fossils much more difficult to reach andremove. To access these fossils, the research team dangles inharnesses and other rock-climbing equipment as high as 15 feetabove the cave floor, carrying drills and other excavation tools.
The main chamber below the Drop Room, known as the atrium,consists of spectacular stalactite formations. The atrium'sceiling is covered with a rock matrix containing the bones of small mammals.
To access the second chamber, Waddle and the others mustpass through a gauntlet of bats, bugs and critters, includingsnakes.
During their most recent trip, Waddle and the other membersof the research team encountered a 5-foot long cobra inside thecave. The team quickly crawled out of the cave to safety whileRoss drove to the nearest town six hours away to retrieve ashotgun. Because he was the best shot of all the researchers inthe party, Steumke was charged with entering the cave andshooting the snake. To celebrate restored peace, each member ofthe research team ate a piece of the cobra, cooked to perfectionon an open fire.
"No one wanted to go back into that cave until we knew thatcobra was dead," Waddle joked.
Waddle will spend the next several months in the safety ofher lab at Colorado State separating the hard breccia from theprimate skull and other large bones taken from the site. Thetechnique involves coating exposed bone with a preservative andsoaking the specimens for several weeks in vinegar or other weakacid to dissolve the calcium carbonates that hold the brecciatogether. Once the specimens are restored, Waddle will take themto the Smithsonian Institution in Washington, D.C., foridentification, using its inventory of primate fossils todetermine whether they represent a new or existing species.
Portions of rock retrieved from the cave where the largestbones were found will be sent to laboratories at the Universityof Georgia for dating.
The above story is based on materials provided by Colorado State University. Note: Materials may be edited for content and length.
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