Irruptive growth occurs when a species reproduces rapidly. It is especially common in large herbivores, such as pronghorn or elk (red deer), which have high fecundity and delayed density-dependent effects on recruitment. All populations show logistic growth, but in species which exhibit irruptive growth this is especially rapid. Populations of some species initially show a lack of response to density-dependent factors that limit population size as it nears the carrying capacity of the environment. The exhibition of irruptive growth is dependent on a number of elements including resource availability, degree of both interspecific and intraspecific competition, and strength of predator-prey relationships. In ecosystems with more than one species feeding on a certain resource, the populations of certain species can irrupt in non-predictable ways depending upon the complex feedback mechanisms caused by competition. A species population may sometimes irrupt when predators are removed, or when favourable weather causes food supplies to rapidly increase.