In ecology, biomass means the cumulation of living matter. That is, it is the total living biological material in a given area or of a biological community or group. Biomass is measured by weight, or by dry weight, per given area (usually measured per square metre or square kilometre).
The most successful animal, in terms of biomass, is the Antarctic krill, Euphausia superba, with a biomass of probably over 500 million tons, roughly twice the total biomass of humans. Biomass may also be a measure of the dried organic mass of an ecosystem.