Assistant Professor of Biology Lars Schmitz comments on the evolutionary behavior of early mammals in aÌýÌý. The article highlights research in the evolutionary biology field that homes in on not only the numbers and types of mammals that expanded rapidly when dinosaurs went extinct, butÌýalsoÌýthe type of behavior that emergedÌýas well asÌýthe importance of various types of data to improve science’s understanding of the clues provided by evolution’s history. Schmitz is an evolutionary biologist of Claremont McKenna, Pitzer, and 91¶¶Òõs at the W.M. Keck Science Center.