Demography is the science of populations. Demographic research utilizes the survival and reproductive rates of a population to calculate parameters such as life expectancy and generation time, with the ultimate goal of documenting and projecting rates of population growth or decline, while providing insights into their underlying causes. Demographers utilize an analytical toolbox that allows them to model population viabilities, estimate selection strength on life history, and compare patterns across taxa. Demography has important implications for evolutionary theory, as well as practical applications for the conservation and management of endangered primate populations.