Credit: D. BOHRER, WHITE HOUSE/AP PHOTO

Proc. Natl Acad. Sci. USA 106, 952–954 (2009)

Predation by humans drives changes in exploited prey much faster than other evolutionary pressures do.

Previous research has shown that commercial fishers and trophy hunters can mould traits such as average size at reproductive age in wild populations, but no single study has revealed the pace at which these changes generally take place. In a meta-analysis of work on the morphology and life histories of 29 species, including fish, mammals and plants, Chris Darimont of the University of California, Santa Cruz and his colleagues found that changes in human-harvested systems occurred more than 300% faster than in natural systems, and 50% faster than in systems affected by other human influences, such as pollution.

The authors suggest that human predation works so quickly because it is often felt by large proportions of the adults in populations.