We are a group of functional anatomists who work on a variety of questions related to understanding the mechanisms through which diet and feeding behaviors have shaped primate evolution. The diversity of primate diets and feeding mechanisms are reflected in the design of skull structures, and teeth and jaws comprise the most abundant fossil record of primate evolution.
Feeding Experiments End-user Database Now Live!
Christine Wall, Ph.D.
My research is primarily lab-based and focused on the biomechanics of mastication and incision. I want to understand how feeding structures work and how variation in function is related to variation in form. This information can then be applied to understanding the adaptive diversity of living and fossil animals. To do this, I use in vivo methods to observe structures at work, and combine these observations with detailed morphological data and statistical analysis. I am particularly interested in muscular, skeletal, and dental specializations to breaking down foods that differ in structural and material properties. An important focus of this work has been to understand (1) the interactions between size and feeding biomechanics, (2) jaw and tooth movements during chewing and other feeding behaviors, and (3) the patterns of activation of the chewing muscles. A recent research direction for the lab is to collect data on the energetic costs of feeding to generate links between what we know from lab-based studies about the morphology and physiology of the feeding apparatus and what we know from field-based studies about feeding ecology and diet.
As a Research Professor Emerita and through my work as a Senior Research Scientist at the Duke Lemur Center, I continue to be active in research and mentoring.
Recent Duke Undergraduates
- Ahmed Ahad (B.S., 2019) - temporomandibular joint biomechanics and shape sexual dimorphism in humans and other anthropoid primates
- Daniel Doyle (B.S., 2018) - lower limb fiber phenotype, locomotor biomechanics, and daily travel distance in apes
- Kavita Jain (B.S., 2017) - microCT, iodine staining and three-dimensional architecture of jaw muscles of lemurs and Saimiri sciureus
- Aidan Fitzsimons - conservation of motor pattern and EMG signal processing
- Dr. Janine Chalk - Assistant Professor, Mercer School of Medicine
- Annie Chen - University of North Carolina Dental School
- Amalia Cong - University of Toronto Dental School
- Dr. Anne Claire Fabre - Museum National d'Histoire Naturelle, FUNEVOL, Paris
- Sachin Govil - M.S., Dept. of Biomedical Engineering, Duke University
- Dr. Jennifer Hotzman - Adjunct Assistant Professor, University of Southern Mississippi
- Kim Le - M.S., Department of Anthropology, University of Florida; P.A., Duke University
- Michael McLennon – University of Maryland Dental School
- Courtney Orsbon - M.D./Ph.D. student, University of Chicago, Pritzker School of Medicine
- Gowri Ramachandran, M.D. - Department of Psychiatry, George Washington University
- Emma Santoianni - University of Wisconsin
- Ben Schwartz - M. D. student
- Daisy Song - M.S. Biomedical Sciences, Mississippi State University
- Dr. Elizabeth St. Clair, Center for Functional Antomy and Evolution, Johns Hopkins University
- Dr. Maxx Toler, Assistant Professor, Campbell University
- Christine Wu – M. D. student, Wake Forest University
- Rex Ying - Ph.D. student, Computer Sciences, Stanford University
Energetic Costs of Feeding in Primates
This is a long-term project to collect novel data on the energetic costs of feeding behaviors in primates. Animals eat because they need energy to live and reproduce, but we know almost nothing about how much it costs primates to eat or how these costs are related to the evolution of feeding structures. Respirometry measurements combined with simultaneous digital video recordings are being collected for 14 primate species ranging in size from 60 g (Microcebus murinus) to 80,000 g (human). We are quantifying how the energetic costs of feeding scale relative to body mass, to morphological features such as mandibular size and tooth size, to dietary parameters such as food toughness, size, and strength, and to different types of feeding behaviors. By looking at a variety of feeding behaviors and quantifying the costs of these behaviors, we will generate a more comprehensive understanding of the selective pressures related to diet and food choice in primates. During 2015, we will be busy collecting respirometry data on strepsirrhines at the Duke Lemur Center and on Old World monkeys at the Duke Vivarium. Collaborators on this project are Jandy Hanna, Matt O’Neill, Ken Glander, Jonathan Perry, and Janine Chalk
- Wall et al. (2010)
Evolution of Human Diet
This is a collaborative project with Greg Wray (Duke, Dept. of Biology) and Sarah Tishkoff (University of Pennsylvania, Dept. of Genetics) that brings together a group of researchers attempting to link genomics, physiology, and morphology to study the evolution of diet in humans and chimpanzees.
- Fedrigo et al. (2011)
- Babbitt et al. (2010)
Evolutionary Genomics of Enamel Thickness in Hominoids
The focus of this research is to document the genomic variation associated with the thick enamel phenotype that distinguishes humans from other extant hominoids. We are comparing sequence similarity in eight genes and their upstream regulatory regions. These genes code for the structural extracellular matrix proteins and the enamel proteases involved in amelogenesis. The thick enamel phenotype of modern humans differs dramatically from the thin enamel of Pan and Gorilla. We hypothesize that the evolution of thick enamel in humans is linked to genetic changes in the regulatory regions of genes coding for enamel matrix proteins or the associated proteases.
Recently, we reported the early results of this work at the American Association of Physical Anthropologists Meeting in Portland, Oregon (link here to pdf of poster) and at the Biology of Genomes Conference in Cold Spring Harbor, New York. Collaborators on this project are Julie Horvath, Greg Wray, Jukka Jernvall, Gowri Ramachandran, Olivier Fedrigo, B.J. Nielsen, Courtney Babbitt, Anthony Moore, and Lisa Pfefferle.
- Horvath et al. (2012a,b)
Mathematical Modeling of Occlusal Contacts During the Power Stroke
This is a collaborative project to generate new variables that measure how the potential for puncture, shear, and crush along a toothrow in functional occlusion changes depending on the relative positions of the upper and lower dentition throughout the tooth-tooth contact period of the power stroke of mastication. It brings together functional morphologists and mathematicians to generate novel computational algorithms to describe tooth movements during the power stroke and quantify relationships among tooth surface structures. The “occlusal energy” variables will be used to evaluate occlusal morphology in relation to diet in extant and extinct primates. Collaborators on this project are Ingrid Daubechies, Doug Boyer, Yaron Lipman, Liz St. Clair, Jonathan Perry, Tong Wu, and Siobhan Cooke.
Integrative Studies of Mammalian Feeding – The Feeding Experiments End-User Database (Feed)
In collaboration with many experimental functional anatomists and physiologists in the U.S. and Europe, and the National Evolutionary Synthesis Center (NESCent, Durham, NC), we have released a relational database (the Feeding Experiments End-user Database, or FEED) that is an archive for existing in vivo data and a repository for future work on feeding physiology in mammals. The analyses that we are just beginning to undertake using FEED are an important step in research on mammalian feeding physiology because they will help us connect variation in feeding physiology to broad-scale patterns of mammalian evolution and diversification. This project includes the development of several FEED-specific ontologies designed to link up with the rapidly expanding set of anatomical, behavioral, and functional ontologies being generated in the larger biological community. Collaborators on this project are Robert Druzinsky, Vladimir Gapeyev, Rebecca German, Hilmar Lapp, Chris Vinyard, Susan Williams. The Research Coordination Network provides invaluable assistance in developing the ontologies. FEED can be accessed at www.feedexp.org
- Wall et al. (2011)
- Vinyard et al. (2011)
- Williams et al. (2011)