| the roles of predator maturation delay and functional response in determining the periodicity of predator-prey cycles. | population cycles in small mammals have attracted the attention of several generations of theoretical and experimental biologists and continue to generate controversy. top-down and bottom-up trophic regulations are two recent competing hypotheses. the principal purpose of this paper is to explore the relative contributions of a variety of ecological factors to predator-prey population cycles. here we suggest that for some species - collared lemmings, snowshoe hares and moose in particular - matu ... | 2009 | 19563815 |