Dr. Sue McDonnell is a native Pennsylvanian, raised in a dairy farming family in the anthracite coal regions north of Scranton. She holds a 1982 master’s degree in Psychology from West Chester University and a 1985 PhD in Reproductive Physiology and Behavior from the University of Delaware. She completed post doctoral study in clinical veterinary reproduction at the University of Pennsylvania’s New Bolton Center in 1987 and became board certified in Applied Animal Behavior in 1991. She is the founding head of the Equine Behavior Program at the University of Pennsylvania School of Veterinary Medicine, where her work includes clinical, research, and teaching activities focused on horse behavior. Dr. McDonnell includes all types of behavior in her clinical case load, with stallion behavior as an area of particular interest and expertise.

Dr. McDonnell’s research interests include several areas within equine physiology, behavior and welfare. She has also traveled to study equids throughout the world. In addition to laboratory and field studies, she maintains a semi-feral herd of ponies specifically for the study of their physiology and behavior under semi-natural conditions. This affords veterinary and animal behavior students the opportunity for long-term observation of equine social and developmental behavior and for first-hand comparison of horse behavior under free-running and traditional domestic conditions.

Dr. McDonnell is the author of two introductory level books on horse behavior entitled Understanding Horse Behavior, and Understanding Your Horse's Behavior, published by The Blood Horse in their Horse Health Care Library Series, and the recently released catalog of horse behavior, The Equid Ethogram, A Practical Field Guide to Horse Behavior, published by Eclipse Press. Along with Dr. Danny Mills, she co-edited The Domestic Horse: Evolution, Development and Management. Among Dr. McDonnell's honors are The George Stubbs Award given by the American Association of Equine Practitioners for contributions to equine veterinary medicine by a non-veterinarian and a Gold Medal from the Agricultural University of Krakow, Poland, their highest honor for distinguished scientific collaboration.