National Geographic : 2010 Aug
whales, supremely adapted swimming ma- chines, descended from land mammals that once walked on all fours. Gingerich has devoted much of his career to explaining this metamor- phosis, arguably the most profound in the ani- mal kingdom. In the process he has shown that whales, once celebrated by creationists as the best evidence against evolution, may be evolu- tion's most elegant proof. "Complete specimens like that Basilosaurus are Rosetta stones," Gingerich told me as we drove back to his eld camp. " ey tell us vastly more about how the animal lived than fragmen- tary remains." Wadi Hitan---literally "valley of whales"--- has proved phenomenally rich in such Rosetta stones. Over the past 27 years Gingerich and his colleagues have located the remains of more than a thousand whales here, and countless more are le to be discovered. When we pulled into camp, we met several of Gingerich's team members just back from their own eldwork. We were soon discussing their results over a dinner of roast goat meat, foul mudamas (fava bean puree), and atbread. Mohammed Sameh, chief ranger of the Wadi Hitan protected area, had been prospecting for whales farther to the east and reported several new bone piles---fresh clues to one of natural history's great puzzles. Jordanian postdoc Iyad Zalmout and grad stu- dent Ryan Bebej had been excavating a whale rostrum poking out of a cli face. "We think the rest of the body is inside," said Zalmout. of whales and of all other land animals was a atheaded, salamander- shaped tetrapod that hauled itself out of the sea onto some muddy bank about 360 million years ago. Its descendants gradually improved the function of their primitive lungs, morphed their lobe fins into legs, and jury-rigged their jaw joints to hear in the air instead of water. Mam- mals turned out to be among the most success- ful of these land lovers; by 60 million years ago they dominated the Earth. Whales were among a tiny handful of mammals to make an CT scans of Basilosaurus bones, including this long, slender jaw, will be used for a digital model showing how the whale moved, swam---and chewed.