STEM Shoutout: Dr. Felisa Smith

UNM biologist studies body size of animals to analyze loss of biodiversity


Dr. Felisa Smith, a professor in the Department of Biology at UNM, heads up a collaborative research team investigating the ecological consequences of the late Pleistocene extinction of large-bodied mammals in North America.  


“Today, the majority of large-bodied mammals around the globe are either listed as vulnerable or endangered. A major focus of conservation biology is geared towards developing an understanding of how their loss may impact contemporary ecosystems,” Smith said. “Looking to the past and seeing how animals and earth systems responded to the terminal Pleistocene megafauna extinction can provide important insights.”


Smith earned her Ph.D. in 1991 from the University of California at Irvine and came to UNM as a postdoc shortly thereafter. She was hired as a tenure-track faculty member in the Department of Biology, and collaborates across many disciplines, including paleoecology, macroecology, biogeography and geology. Much of her work is focused on the ecological and evolutionary responses of animals to environmental change.


Overall, Smith hopes to assist conservation biologists by characterizing the key role megafauna play in environments. This work has taken her in some interesting directions; for example, she pioneered the use of ancient packrat middens to investigate small mammals response to late Quaternary climate change, and she was the head of a research team that examined the body size of mammals over their entire evolutionary history. More recently, she headed up a group that analyzed the body size patterns of all major clades of life over the past 3.6 billion years of earth history.


Smith’s 2018 NSF-funded study entitled Body size downgrading of mammals over the late Quaternary, which was recently published in Science, shows that, “body-size downgrading – the loss of the largest species on each continent over time – is a hallmark of human activity, both in the past and present. If this trend continues into the future researchers warn, the largest terrestrial mammal in 200 years will be the domestic cow,” according to a story in the UNM Newsroom by Steve Carr.


Smith’s current work exploring the loss of biodiversity in the late Pleistocene focuses on changes of abundance, distribution, diet, and morphology of the surviving animals before and after the extinction of the largest animals in the ecosystem.


“We characterize abundance and distribution shifts by using occurrence information from fossil database compilations, morphology and size are determined by using 2 and 3D imaging of fossil limbs and molars, and we examine changes in diet by using stable isotope analysis.” Smith said. “Because we have a continuous 22,000 year record at our site in Texas, we can look at responses to climate changes as ice sheets retreated as well as to the influence of biodiversity loss. It’s an amazing record.”