Antarctic krill and humans occupy nearly equal positions in global biomass estimates, according to recent studies, though neither ranks as the planet's most abundant life form by mass. Human collective weight measures approximately 350 million metric tons, while krill reach 379 million metric tons, placing both near the top among animal species. Cattle surpass both with an estimated 650 million metric tons of biomass, representing the largest animal biomass on Earth.

Plants dominate terrestrial biomass, with global carbon mass measurements indicating 450 billion tons of plant carbon compared to 70 billion tons of bacterial carbon and 12 billion tons of fungal carbon. Domesticated crops like sugar cane lead agricultural production, with 2023 harvests totaling 2 billion metric tons—six times the combined weight of all humans. Wild trees also contribute significantly, particularly boreal forest species such as black spruce and Dahurian larch, whose combined biomass exceeds 19 billion metric tons.

The Bar-On et al. 2018 study provides the most comprehensive kingdom-level biomass assessment, measuring carbon content rather than total mass to analyze energy flow through ecosystems. This approach reveals plants contain nearly three times more carbon than all animal life combined, while bacteria and archaea collectively outweigh animals in carbon mass. These figures underscore the disproportionate ecological influence of primary producers despite animals' visible prominence in human experience.