WITH an average altitude of over 4000 metres, Tibet – the “roof of the world” – towers over its neighbours. So massive is the plateau that it alters weather patterns, bringing India its monsoons. But it was not always so. The region went through a growth spurt only 7 million years ago, much more recently than previously thought.
Yang Wang of Florida State University, Tallahassee, and her colleagues collected fossil horse and rhino teeth in 7-million-year-old sediments in the high Himalayas of southern Tibet. Carbon isotope analysis of the teeth showed that the animals dined on grasses containing carbon 4, which are…
