Published 2026-09-13 · data 2023 · 100% of mammal biomass
Wild mammals are a rounding error
Weigh every mammal on Earth. Livestock take most of the mass. Humans take most of the rest. Everything that still lives wild — whales, deer, rats, bats — shares the last sliver.
Wild mammals are a rounding error. In 2023, livestock carried 59% of the world's mammal biomass and humans 36%; everything still wild — whales, deer, rats, bats — shared the last 5%. The grid weighs mass, not headcount: a square of cattle is the same tonnes as a square of whale.
1 cell = 1.1 million tonnes of wet mammal biomass (0.1% of mammal biomass) · 1,000 cells
Context
The figures come from Greenspoon et al.'s 2023 assessment in PNAS: roughly 630 million tonnes of livestock, 390 million tonnes of humans, and 60 million tonnes of wild mammals — about 1.08 billion tonnes of wet mammal biomass in total. That works out to some 17 tonnes of humans and livestock for every tonne of wild mammal.
Even the wild sliver leans oceanic: roughly 40 million tonnes of wild mammal mass is marine, against about 20 million tonnes on land.
Because the grid weighs mass rather than headcount, one wild-mammal square can stand for vast numbers of small animals while a livestock square stands for far fewer, heavier ones. The ledger covers mammals only — birds, fish, reptiles, and insects sit outside it.
Greenspoon et al. 2023 (PNAS): livestock ≈630 million tonnes, humans ≈390 million tonnes, wild mammals ≈60 million tonnes (about 20 land + 40 marine). Shares rounded onto 1,000 equal cells. This grid is mass, not headcount — one blue square is the same tonnes as one orange square.
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Credit this grid as Inagrid — https://inagrid.com/e/2026-09-13-wild-mammals