J.G.M. ‘Hans’ Thewissen has studied the paleontology, anatomy, and embryology of whales for more than three decades, and has traveled the world to study fossil and living whales. In Pakistan, he discovered skeletons of the first whales, Pakicetus and Ambulocetus, the latter dubbed as the smoking gun of whale evolution by Steven Jay Gould. He documented how dolphin embryos first grow tiny limbs and then, by switching off some key genes, totally loose their hind limbs.  His work on the sense organs of extant whales on Alaska’s North Coast has implications for management of endangered whale populations in the Arctic.  He has published more than 100 scientific papers, nine of which in the prestigious journals Science and Nature.  He is one of three editors of the Marine Mammal Encyclopedia, now in its third edition.  He also wrote a popular book on the origin of whales, ‘The Walking Whales’ (University of California Press). A native of the Netherlands, he holds degrees in biology and geology from the University of Utrecht and the University of Michigan and teaches anatomy and embryology to medical students at Northeast Ohio Medical University.  He also has appointments at Kent State University and the Cleveland Museum of Natural History. Scientist in Residency Fellow, March