Research geologist and curator of fossil marine mammals, Smithsonian Institution's National Museum of Natural History. Author of the popular science book "Spying on Whales." Research focuses on the repeated and convergent evolution of marine life, including iconic species such as sea turtles, sea cows, and whales. Each of these lineages have adapted to life in the water from land-based ancestors; the fossil record shows us how these evolutionary changes happened, from sites around the world. Many of these iconic marine animals are also highly threatened or endangered in today’s oceans; much of collaborative research involves working on ecological and anatomical projects using data from living species, as well. As a result, has gone on scientific expeditions to every continent; and discoveries made with collaborators, in over 60 scientific publications, have been exhibited in major museums across the Americas. Ultimately, knowing how and why these iconic species have changed over geologic time is crucial for understanding their fates during the Anthropocene (Earth during the age of humans), as their potential futures relate to past oceans as much as it does from human threats (e.g., whaling).