Yak Grazing in the Lhasa Region of Tibet (IMAGE) Max Planck Institute of Geoanthropology Caption Large grazing animals have a strong selective force on plants, certain plants have evolved traits to thrive on pastoral landscapes. Spengler and Mueller theorize that yak herding may have helped drive buckwheat domestication in the southern Himalaya. This lone yak in the Lhasa region of Tibet is a significant evolutionary force on the plant communities around where it grazes. Credit Robert Spengler Usage Restrictions This image may only be used in the context of reporting on this publication and with appropriate credit information. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.