Daniel “Dan” Rubenstein transferred to emeritus status on July 1, 2023. As the Class of 1877 Professor of Zoology and professor of ecology and evolutionary biology, Dan served Princeton and the broader scientific and public communities through his teaching, serving as department chair of ecology and evolutionary biology for more than two decades, his establishment and guardianship of the Mpala Research Centre in Kenya, and his years of service to the Hopewell Valley Open Space, the Hawk Mountain Sanctuary, Earthwatch, and other environmental groups.

Dan’s contributions range across the spectrum of what makes a great citizen scholar; he is also a terrific lecturer, blending passion for science and teaching with unquestionable authority. He has been a major contributor to theory and experiment in animal behavior for nearly fifty years, and his work brilliantly integrates the two. He is especially noted for his research on the social dynamics of mammalian groups, which crosses scales and disciplines easily, and integrates perspectives from immunology to populations to ecosystems. Moreover, although he is one of the world’s experts on mammalian social behavior, he has also contributed substantially to our understanding of social behavior and functional morphology in birds, fish, herps, and invertebrates. He is both broad and deep, exploring issues of cooperation and spite, evolution and ecology, biocomplexity, and the management of common-pool resources. Most recently he has built on his expertise to address the global food and agriculture system, and impacts on and of farming practices. In fact, he has worked closely with Princeton Campus Dining to blend his research on agricultural and dining practices into a popular undergraduate course.

Dan has made important contributions to the study of social evolution for nearly five decades. His early studies on zebras led to a career of comparative work on animal social behavior that continues to this day.

His long-term studies have helped define our understanding of mammalian societies. He began studying zebras in Africa, both the plains zebra that lives in male-led harem social groups and the endangered Grevy’s zebra that lives in female-only groups. He later studied wild horses on a barrier island off the coast of North Carolina, onagers — Asiatic wild asses — that were being reintroduced to Israel, wild asses in India, and Przewalski’s horses in Mongolia, among others, emphasizing the role that extrinsic factors like predation and food availability have on animal social behavior. He has been recognized for these research accomplishments with numerous awards, including the National Science Foundation’s Presidential Young Investigator Award, the Society of Sigma Xi’s John P. McGovern Science and Society Award, and the Animal Behavior Society’s Exemplar Award. He was also elected as a fellow of the American Association for the Advancement of Science and as a member of the American Academy of Arts and Sciences.

Dan has a unique ability to work integratively with disciplines and collaborators outside of biology. During his early years, he developed game-theoretic models of social evolution, and later dynamic models of population processes. His game theory models on risk and uncertainty are as important today as they were novel then for a field that is growing again because of rapid anthropogenic climate change, which is resulting in increased climatic uncertainty across the globe. His population models have been used by the U.S. National Park Service to regulate wild horse numbers on barrier islands and by the Kenya Wildlife Service to study trophy hunting. He has worked with computer scientists to develop a new generation of radio collars to track zebras across a dynamic African landscape.

Most recently, he has been working with engineers to develop computer software that can barcode zebras automatically from photographs in seconds. Working with the Kenya Wildlife Service, he led the first full direct sight census of the endangered Grevy’s zebra using this software. Using citizen science to help ground-truth the software and images, his team is applying this technology to elephants, giraffes, whale sharks, and more, with the ultimate goal of being able to census animal populations globally using cloud computing. Finally, he is now working with engineers to once and for all determine why zebras have stripes. Using populations of zebra sub-species across Africa, as well as captive populations in the U.S., he hopes to distinguish among many of the long-untested hypotheses for whether stripes provide camouflage, confuse predators, confuse biting flies, or cool the animals.

As Dan’s research career blossomed, outreach became as important to him as the science. He has employed large numbers of scouts in local communities in Northern Kenya for years to help observe Grevy’s zebra and monitor human-wildlife interactions. Along with his wife, Nancy, he has led the creation of the Northern Kenya Conservation Clubs, which help prepare Kenyan youth for a lifetime of conservation through experiential learning and teaching.

As part of his outreach efforts, Dan has been involved in numerous conservation organizations around the world. He has long been on the board of Earthwatch and Earthwatch International, organizations that connect the public with active research projects around the world. He gives more than a dozen lectures a year, often to the public. He has been a member of the International Union for Conservation of Nature Equid Specialist Group, and has advised the Kenya Wildlife Service, the U.S. National Park Service, and the U.S. National Academies of Sciences on equid conservation and management. He has been president of the Animal Behavior Society, as well as president of the Princeton chapter of Sigma Xi, and is a longtime board member of the Friends of Hopewell Valley Open Space, working tirelessly to preserve land across New Jersey. He is a prominent member of the Board of Directors for Princeton’s Mpala Research Trust, and has raised millions of dollars for conservation and development for Princeton in Africa and beyond. He helped establish the Foundation and Research Centre more than twenty years ago.

Dan is also a wonderful teacher. In 1999, he won Princeton’s President’s Award for Distinguished Teaching, a great testimonial to both his teaching efforts in the classroom and on undergraduate field courses in Kenya and Panama. Over his forty-plus year tenure at Princeton, Dan Rubenstein has made important contributions in science, education, and outreach. His long-term comparative work on social evolution in equids has shaped the way we think about how the environment influences social behavior in all animals. His continued use of new tools and technologies has helped to push the field forward while making strong links to conservation. At the same time, he has helped educate computer scientists and engineers with his integrative work. His continued outreach in Africa has shaped the lives of hundreds if not thousands of people, and the skills he is teaching children and adults will continue to not only improve their livelihoods, but also help to protect threatened and endangered species.

Dan’s devotion to and leadership at Princeton have led to the development of new programs and centers, and touched the lives of hundreds of students. He will surely continue his involvement even in retirement.

Written by members of the Department of Ecology and Evolutionary Biology faculty.