A Michigan native, Duane Ullrey completed a BS degree in animal husbandry (1950) and an MS degree in animal pathology (1951) from Michigan State College. Duane earned a PhD in animal nutrition with minors in physiology and biochemistry (University of Illinois, 1954). Upon graduation, he taught at Oklahoma A&M University. In 1956, Duane was hired as an assistant professor, becoming a full professor in 1968, of animal nutrition with a joint appointment in Departments of Animal Science and Fisheries and Wildlife at Michigan State University. He taught and conducted research in swine and white tailed deer nutrition, as well as taught Animal Nutrition in the College of Veterinary Medicine, ultimately developing a Comparative Animal Nutrition program. Duane influenced many (34 graduate students, 140 graduate committees) in formal and informal learning environments. Duane established new care standards in the field of zoo animal nutrition. His comparative approach facilitated service on prominent committees, including the National Academy of Sciences, Committee on Animal Nutrition (1981; Chair, 1985), Lab Animal Nutrition (1978), Mineral Toxicity (1980), Horse Nutrition (1989), and Primate Nutrition (Chair, 2003). Duane was recognized by his colleagues with honors, including the MSU Distinguished Faculty Award (1983), ASAS Morrison Award (1988), ASAS Fellow (1990), the first Comparative Nutrition Society honorary life member (1996), and the first award recipient of the Duane E. Ullrey Achievement Award by the American Association of Zoo Veterinarians (1999). Duane was a mentor, friend and colleague. He cultivated sound scientific principles in species husbandry, emphasized a strong foundation in nutrition, and guided our comparative discovery of relevant similarities and differences among novel species with known models. A consummate life-long learner, Duane embodied integrity, thoughtfulness, humor, honesty, and perseverance in his personal and professional life. Through his students, he continues to make remarkable contributions in academia, industry, and regulatory agencies in areas of animal agriculture, wildlife and natural resource management, veterinary medicine, and human nutrition and health.