Dr. Nicholas Pyenson is the Curator of Fossil Marine Mammals at the Smithsonian's National Museum of Natural History and studies the paleobiology of marine mammals, and, more broadly, of other marine tetrapods. The evolution of whales, for example, is just one case of several mammalian lineages that have made a series of independent transitions from terrestrial to marine lifestyles at different times during the past 55 million years. Each group of marine mammals has undergone dramatic evolutionary transformations from their terrestrial ancestries, with attendant modifications to multiple anatomical, behavioral and ecological systems. These multiple transitions provide a series of evolutionary comparisons that form the basis for understanding how marine mammals have diversified in the oceans.
Nick is also interested in the evolutionary and ecological histories of other marine tetrapods, four-limbed animals, that have that made the great transition from life on land to life in the sea. The scope of these investigations primarily focuses on marine rocks from the Cenozoic, including a broad array of field localities in both the Northern and Southern hemispheres.