On the regulation of populations of mammals, birds, fish, and insects

Richard M. Sibly*, Daniel Barker, Michael C. Denham, Jim Hone, Mark Pagel

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


A key unresolved question in population ecology concerns the relationship between a population's size and its growth rate. We estimated this relationship for 1780 time series of mammals, birds, fish, and insects. We found that rates of population growth are high at low population densities but, contrary to previous predictions, decline rapidly with increasing population size and then flatten out, for all four taxa. This produces a strongly concave relationship between a population's growth rate and its size. These findings have fundamental implications for our understanding of animals' lives, suggesting in particular that many animals in these taxa will be found living at densities above the carrying capacity of their environments.

Original languageEnglish
Pages (from-to)607-610
Number of pages4
Issue number5734
Publication statusPublished - 22 Jul 2005


Dive into the research topics of 'On the regulation of populations of mammals, birds, fish, and insects'. Together they form a unique fingerprint.

Cite this