UMMP Postdoctoral Researcher Fabian Hardy, Research Scientist Catherine Badgley, and their colleagues set out to understand how mammals adapted to changing environments in the American southwest during the Miocene. The team gathered carbon and oxygen isotopic data from hoofed mammals and soil carbonates in the Mojave region from 17-8 million years ago to see if they could spot change in the mammals’ diets as the dominant kinds of plants changed over time. What they found was a surprise. Rather than switching diets, herbivores in the region tracked their preferred food resources and consumed familiar plants for at least 9 million years as forest-dominated settings changed to more open woodland and grassland habitats. These conservative diets suggest the mammal species were consuming plants from outside of the immediate basin where their fossils were preserved, highlighting the importance of habitat connectivity during periods of climate and vegetation change. Hardy’s results also provide tantalizing evidence for facultative drinking behavior–obtaining more water from leaves than drinking it directly–in extinct camels and pronghorn. If correct, this suggests an earlier evolution of the adaptation than previously known in these groups. The study, “Dietary fidelity of Miocene ungulates in the context of environmental change in the Mojave region, western North America”, appears in Palaeogeography, Palaeoclimatology, Palaeoecology.
