Predators are typically larger than their prey by

Value 4 orders of magnitude
Organism Biosphere
Reference Butterfield NJ, Macroevolution and macroecology through deep time, Paleontology, Volume 50, Issue 1 January 2007 Pages 41–55, DOI: 10.1111/j.1475-4983.2006.00613.x link p.48 left column 2nd paragraph
Primary Source Brown et al., 2004. Toward a metabolic theory of ecology. Ecology, 85, 1771–1789. DOI: 10.1890/03-9000 link
Comments P.48 left column 2nd paragraph: "With the body mass of pelagic organisms extending over 20 orders of magnitude, and predators typically four orders of magnitude larger than their prey (primary source), some 80 per cent of modern marine biomass is likely to be eumetazoan [not including heterotrophic ⁄ chemoautotrophic prokaryotes (see Whitman et al. 1998), but also not including the considerable biomass of benthic metazoans, which also exhibit an essentially flat biomass spectrum (Schwinghamer 1983, Kerr and Dickie 2001)]."
Entered by Uri M
ID 113592