Christine Janis

Christine Marie Janis is a British–American palaeontologist whose work focuses on mammalian evolution. She is Professor Emerita of Biology at Brown University and Honorary Professor in the School of Earth Sciences at the University of Bristol. Her research examines the evolution of mammalian diet and locomotion, particularly in relation to climatic and environmental change during the Cenozoic.

Janis's research has addressed mammalian herbivory, limb biomechanics, and locomotor evolution, with a focus on ungulates, carnivorans, and macropodoid marsupials (kangaroos). She has received several professional honors, including the George Gaylord Simpson Prize and the Romer-Simpson Medal. She is an elected Fellow of the American Academy of Arts and Sciences.

Early life and education Janis earned a bachelor's degree in Natural Sciences (Zoology) from the University of Cambridge in 1973, and a PhD in Organismal Biology (Vertebrate Paleontology) from Harvard University in 1979.

Academic career Janis joined Brown University in 1983, where she served as assistant professor, associate professor, and professor of biology until her retirement in 2016, when she was appointed Professor Emerita. She has also served as an honorary research associate at the Field Museum of Natural History in Chicago.

Since 2019, Janis has been a member of the advisory board of the NOW (New and Old Worlds) Database of Fossil Mammals, a global resource for documenting Cenozoic mammalian occurrences and supporting macroevolutionary and palaeoecological research.

Scientific contributions Janis's research examines the evolution of Cenozoic mammals, with particular attention to relationships between morphology, behaviour, and environmental change. Her work integrates fossil evidence with functional and biomechanical analyses to reconstruct diet, locomotion, and ecological adaptation in both living and extinct mammals. Much of her research focuses on ungulates, carnivorans, and macropodoid marsupials (kangaroos).

Janis's first publication addressed competition between horses and ruminant artiodactyls, a topic she continued to investigate later in her career and revisited in recent work on the drivers of late Cenozoic equid evolution.

She has contributed to research on mammalian herbivory through analyses of dental morphology and wear, particularly in relation to the evolution of hypsodont (high-crowned) cheek teeth. This work includes quantitative studies of dental traits in living ungulates and examinations of the relationships between tooth form, feeding ecology, palaeoenvironmental reconstruction, and adaptive responses to increasingly abrasive diets. Janis has also conducted research on ruminant artiodactyl systematics and on patterns of Cenozoic mammalian evolution in relation to climate change. Her work has contributed to broader analyses of how long-term environmental change is associated with mammalian diversity and ecological specialisation.

From the 1990s onward, Janis published extensively on mammalian locomotion and limb biomechanics, demonstrating how limb proportions, joint morphology, and scaling relationships can be used to infer locomotor behaviour in extinct mammals. This research has provided a functional framework for interpreting postcranial fossil material across a range of mammalian groups.

Her publications also include studies of the predatory behaviour of marsupial carnivores, incorporating biomechanical and functional analyses that have been reported in popular science media.

In more recent research, Janis has examined the evolution of horse locomotion, particularly hypotheses concerning the evolution of a single functional toe in modern horses. She has also contributed to research on kangaroo locomotion, proposing that extinct short-faced giant kangaroos (sthenurines) used bipedal walking rather than hopping. This interpretation was later supported by fossil trackway evidence. Beyond mammals, Janis has published on the palaeobiology of other fossil vertebrates, including early vertebrates, early tetrapods, dinosaurs, Mesozoic mammals, and the timing of divergence among placental mammal lineages.

Honors and awards George Gaylord Simpson Prize, Yale University (1985) Fellow, The Paleontological Society (2007) Elizabeth Leduc Award, Brown University (2008) Honorary Member, Society of Vertebrate Paleontology (2019) Elected member, Linnean Society of London (2022) Romer-Simpson Medal, Society of Vertebrate Paleontology (2024) Elected member, American Academy of Arts and Sciences (2025)

Books Janis has authored and edited several widely used textbooks and edited volumes on vertebrate evolution and mammalian palaeontology. These include seven editions of Vertebrate Life (1998–2023), with Harvey Pough as senior author, and two volumes of the reference work Evolution of Tertiary Mammals of North America (1998, 2008), for which she served as senior editor.

Selected publications Janis, C. M. (1976). (awarded the George Gaylord Simpson Prize) Janis, C. M.; Fortelius, M. (1988). Garland, T. Jr.; Dickerman, A. W.; Janis, C. M.; Jones, J. A. (1993). Janis, C. M. (1993). Pough, F. H.; Janis, C. M.; Heiser, J. B. (1999). Foote, M.; Hunter, J. P.; Janis, C. M.; Sepkoski, J. J. Jr. (1999). Janis, C. M.; Damuth, J.; Theodor, J. M. (2002). Damuth, J.; Janis, C. M. (2011).

Personal life In addition to her research on fossil horses, Janis has been a life-long equestrian. She was married to palaeontologist Jack Sepkoski (1948–1999).

Public engagement Janis has contributed to public understanding of science through radio and television appearances, including participation in BBC Radio 4's In Our Time. She served as a scientific advisor for the Netflix documentary series Life on Our Planet (2023), and has provided extensive advisory input for a forthcoming BBC television series on evolution.