My research attempts to understand behavioral and life-history variation among humans from a socioecological and evolutionary perspective. My research and teaching goals focus on situating modern human variation in development, behavior and life-history against a backdrop of variation in other primates and other mammals. For example, I am especially interested in using comparative analyses to study the evolution of long, slow-growing (yet large-brained) juvenile periods in humans as this is arguably the most derived human trait, driven by our early age at weaning and delayed growth spurt. I have conducted research in Brazil, Paraguay, Bolivia, and Suriname with hunter-gatherers and subsistence horticulturalists. I loosely collaborate with an international team of researchers working around the globe and who share a common interest in quantifying age-specific rates of growth, fertility and mortality. You may download the comparative human life history database here. (Excel)
My colleagues and I have found evidence that high mortality associates with population density, faster body growth, and earlier menarche and reproduction. There is also evidence for a trade-off between number and size of offspring across and within societies, an empirical pattern well-supported in other animals. I use these growing databases as a keystone for introducing students to a wide variety of topics that relate to the evolution of growth, senescence, mating and parenting.
More recently I have become interested in reconstructing population and cultural histories for lowland South American language families using phylogenetic methods. Opportunities abound in South America and around the world for students to conduct research in some of these ongoing fieldsites as well as develop new fieldsites in other communities. In my courses, I strongly encourage students to gain hands-on experience in data analyses in an attempt to place confidence in their ability to conduct publishable research.
Publications
Burger, O., R. S. Walker, and M. J. Hamilton (2010) Lifetime reproductive effort in humans. Proceedings of the Royal Society B 277:773-777. [pdf]
Hamilton, M. J., O. Burger, J. P. DeLong, O. Burger, R. S. Walker, M. Moses, and J. H. Brown (2009) Population stability, cooperation and the invasibility of the human species. Proceedings of the National Academy of Sciences
vol. 106: 12255–12260. [pdf]
Walker, R. S., M. Gurven, O. Burger, and M. J. Hamilton (2008) The trade-off between number and size of offspring in humans and other primates. Proceedings of the Royal Society B 275:827-833. [pdf]
Walker, R. S. and M. J. Hamilton (2008) Life history consequences of density dependence in the evolution of human body sizes. Current Anthropology 49:115-122. [pdf]
Hamilton, M. J., B. T. Milne, R. S. Walker, O. Burger, and J. H. Brown (2007) The complex structure of hunter-gatherer social networks. Proceedings of the Royal Society B 274:2195-2202. [pdf]
Hamilton, M. J., B. T. Milne, R. S. Walker, and J. H. Brown (2007) Nonlinear scaling of space use in human hunter-gatherers. Proceedings of the National Academy of Sciences, USA 104:4765-4769. [pdf]
Hill, K., A. M. Hurtado, and R. S. Walker (2007) High adult mortality among Hiwi hunter-gatherers: Implications for human evolution. Journal of Human Evolution 52:443-454. [pdf]
Walker, R. S., O. Burger, J. Wagner, and C. Von Rueden (2006) Evolution of brain size and juvenile periods in primates. Journal of Human Evolution 51:480-89. [pdf]
Walker, R. S., M. Gurven, K. Hill, A. Migliano, N. Chagnon, R. De Souza, G. Djurovic, R. Hames, A. M. Hurtado, H. Kaplan, K. Kramer, W. J. Oliver, C. Valeggia, and T. Yamauchi (2006) Growth rates and life histories in twenty-two small-scale societies. American Journal of Human Biology 18:295-311 feature article. [pdf]
Walker, R. S., K. Hill, O. Burger, and A. M. Hurtado (2006) Life in the slow lane revisited: Ontogenetic separation between chimpanzees and humans. American Journal of Physical Anthropology 129:577-583. [pdf]
Gurven, M. and R. S. Walker (2006) Energetic demand of multiple dependents and the evolution of slow human growth. Proceedings of the Royal Society B 273: 835-841. [pdf]
Burger, O., M. Hamilton, and R. S. Walker (2005) The prey as patch model: A marginal gains curve for vertebrate prey. Journal of Archaeological Science 32:1147-1158. [pdf]
Walker, R. S. and K. Hill (2003) Modeling growth and senescence in physical performance among the Ache of Eastern Paraguay. American Journal of Human Biology 15:196-208. [pdf]
Walker, R. S., K. Hill, H. Kaplan, and G. MacMillan (2002) Age-dependency in hunting ability among the Ache of eastern Paraguay. Journal of Human Evolution 42:639-657. [pdf]
Todd, L. C., D. C. Jones, R. S. Walker, P. Burnett, and J. Eighmy (2001) Late archaic bison hunters in Northern Colorado: 1997-1999 Excavations at the Kaplan-Hoover Bison Bonebed (5LR3953). Plains Anthropologist 46:125-147. [pdf]
