DISSERTATION RESEARCH: Endocranial capacity and extinction risk in mammals

Stanford University, Stanford CA

Investigators

Abstract

Of the nearly 5,400 mammalian species alive today, a quarter of them are currently at risk of extinction due to loss of habitat, overexploitation, climate change and other human disturbances. Species not considered to be at risk of extinction are regularly added to the list of threatened species. Identifying species of greater conservation concern before their populations become critically threatened may be more effective and less expensive for protecting mammalian diversity than targeting species already known to have suffered population declines. In the fossil record, species of mammals that have gone extinct had significantly smaller relative brain sizes, (the size of the brain relative to body size), than species that are still alive today. Further, carnivore species listed currently as endangered have significantly smaller relative brain sizes as compared to carnivore species that are not threatened with extinction. Based on this preliminary data, this research project will examine more broadly the relationship between relative brain size and conservation status in order to test the hypothesis that species with larger relative brain sizes may be more successful in the face of environmental change, and thus more resistant to extinction. This project is unique in that it examines both modern mammalian species, using a more comprehensive methodology than has been employed to date, as well as mammalian species over the last 30 million years. A goal of this research project is to produce tools that scientists, governments and conservation organizations can use to identify species that may be extinction-prone. By providing an inexpensive and readily deployable metric for proactively identifying species of concern, and guiding action to stem species loss, this work could provide important insights for conservation science and policy. This research will be disseminated through publications, conference presentations and continued communication with non-governmental organizations. Additionally, the substantial dataset that results from this work will be made available to other researchers and state and federal agencies. This research project will involved high school and undergraduate students in research methods and analysis, and supports the doctoral research of a graduate student.