Kathleen Ritterbush is a paleontologist at the University of Utah. She studies what ocean life was like during and before the time of the dinosaurs. Recent projects include modeling sea shells of extinct squid-like ammonite fossils to test if the animals could swim, and hunting for fossil sea sponges in ancient rocks. Because these ancient rocks are pushed into mountains by the Earth’s shifting surface, fossil hunting takes her across deserts of the American West and up into the Peruvian Andes. She is most interested in what animals flourish after global mass extinction events, and how this is related to world-wide environmental changes.