Michael J. Sheriff is Assistant Professor of Mammalogy and Ecology in the College of gricultural Sciences at Pennsylvania State University. The research focus of his lab addresses one of the fundamental questions in biology: what limits and regulates animals in their natural world? Their approach is to bridge physiology, behavior, and ecology to understand how animals interact with the world around them. As such, they are broadly interested in the underlying physiological mechanisms by which ecological interactions (predation, competition, climate, etc. alter behavior and cause changes in reproduction, survival, and ultimately population demography and community structure.