All the ants on Earth do not outweigh all the humans, despite a popular claim that has circulated for decades. The most comprehensive estimate to date, published in 2022, puts the total biomass of the world’s ants at roughly 12 megatons of dry carbon, which works out to about 20 percent of humanity’s biomass. That is an enormous amount of life for creatures you can barely feel on your skin, but it falls well short of the tonnage our species carries around.
Where the Numbers Actually Come From
The figure that finally put this question to rest came from a 2022 study that synthesized data from 489 individual studies spanning every continent where ants live. The researchers estimated that roughly 20 quadrillion individual ants inhabit the planet, a number so large it barely registers as meaningful. When they converted that headcount into biomass, the total came to about 12 megatons of dry carbon.1PubMed Central. The abundance, biomass, and distribution of ants on Earth That figure exceeds the combined biomass of all wild birds and wild mammals on the planet, which gives some sense of how staggeringly successful ants are as a group. But compared to humans specifically, it represents only about a fifth of our collective mass.
On the human side, global biomass has ballooned in the modern era. Between 1850 and 2020, the human population grew from about 1.2 billion to 8 billion, and average body weight increased by an estimated 30 percent over that same window. Those two factors combined to push total human biomass from roughly 50 megatons to around 420 megatons of wet weight.2Nature Communications. The global biomass of mammals since 1850 Separate analyses have placed the figure at around 390 megatons.3PubMed Central. The global biomass of wild mammals Either way, the gap between ant biomass and human biomass is large enough that the popular claim does not hold up.
Why the Myth Has Been So Persistent
The idea that ants outweigh humans has been repeated by scientists, documentarians, and science communicators for years, and it was not always unreasonable. Earlier in human history, when there were far fewer people, the comparison was much closer. Human biomass in 1850 was only about 50 megatons, meaning ants would have represented a much larger fraction of the total. Go back a few thousand years, and ants may well have rivaled or exceeded human biomass, though nobody had the data to say so at the time.
The myth also stuck because the numbers involved are genuinely disorienting. Twenty quadrillion of anything sounds like it should outweigh eight billion of something else, and intuition fails when the size difference between individual organisms spans six or seven orders of magnitude. A single worker ant might weigh a milligram or two. A single person weighs 60 to 80 kilograms. Your brain is not built to do that multiplication on the fly, so the impressive-sounding ant count wins the vibes contest even though the math does not support it.
Another confounding factor is the difference between “dry carbon” and “wet weight.” Biologists often measure biomass in dry carbon because it strips out water and gives a more stable comparison across very different organisms. Humans are roughly 60 percent water by weight. When the ant study reported 12 megatons of dry carbon and compared it to human biomass, it was comparing dry carbon to dry carbon. If you instead compared the ants’ wet weight to the full wet weight of all humans, the ants would still come out well behind, but the ratio might shift slightly depending on how much water ant bodies retain. The takeaway is the same either way: ants are in the ballpark of one-fifth of our mass, not equal to it and certainly not greater.
How Big Is an Individual Ant?
Part of what makes global ant biomass so impressive is that individual ants are minuscule. But “minuscule” covers a surprisingly wide range. Across 135 species measured in one analysis, worker ant body mass spanned nearly four orders of magnitude, from 0.008 milligrams to 53 milligrams.4Functional Ecology. The size–grain hypothesis and interspecific scaling in ants That means the heaviest worker ants weigh thousands of times more than the lightest ones.
Even within a single genus, the variation is striking. Among fire ants in the genus Solenopsis, dry weight ranges from 0.04 milligrams in the smallest minor workers to about 2.2 milligrams in the largest major workers.5PLoS ONE. The Morphometry of Solenopsis Fire Ants Some species have extreme worker polymorphism, meaning the ants within a single colony vary dramatically in size depending on their role. Soldier ants in some species can be 50 times the weight of the smallest workers in the same nest. This variation matters because any global biomass estimate has to make assumptions about average individual mass, and small shifts in that average, multiplied across 20 quadrillion individuals, translate into large differences in the final number.
Where All Those Ants Live
Ants are not evenly distributed across the planet. They are overwhelmingly concentrated in tropical and subtropical regions, with the highest densities in tropical forests and savannas. In a study of ant diversity and stratification in an Amazonian rainforest, researchers collected 494 species, with 357 of them dwelling on the ground or in leaf litter.6PubMed Central. Ant Diversity and Stratification in an Amazonian Rainforest The canopy hosts a separate community, but the floor is where most of the action is.
One of the persistent challenges in estimating global ant biomass is that underground species remain badly undercounted. Subterranean ants form a distinct community that can include over a hundred species at a single site, and up to 44 percent of those species may be unique to underground habitats and rarely or never show up in surface traps.1PubMed Central. The abundance, biomass, and distribution of ants on Earth Systematic subterranean sampling has been attempted on five continents, but most biomes remain largely under-sampled for underground ants. This means the 20-quadrillion estimate is self-described as conservative. The true number could be higher, though probably not enough to change the outcome of the comparison with humans.
Sampling methods themselves introduce uncertainty. The two most common field techniques for counting ground-dwelling ants are pitfall traps, which capture ants that happen to walk into small cups sunk into the soil, and Winkler litter extractors, which sift through leaf litter to find ants hiding in the debris.7The Great Lakes Entomologist. A Comparison of the Effectiveness of Pitfall Traps and Winkler Litter Samples for Characterization of Terrestrial Ant (Formicidae) Communities in Temperate Savannas Each method catches a somewhat different slice of the ant community, and how long you leave traps in the field matters too. A study in Brazilian tropical rainforest found that increasing both the number of pitfall traps and the exposure time from two days to 14 days changed what you caught and how much.8Sociobiology. A comparison between time of exposure, number of pitfall traps and the sampling cost to capture ground-dwelling poneromorph ants (Hymenoptera: Formicidae) All global estimates are built on thousands of these imperfect local snapshots, then extrapolated outward.
Ants in the Bigger Picture of Life on Earth
To appreciate what 12 megatons of dry carbon means, it helps to zoom out. The total biomass of life on Earth is roughly 550 gigatons of carbon, overwhelmingly dominated by plants at around 450 gigatons. All animals combined make up only about 2 gigatons of carbon.9PubMed Central. The biomass distribution on Earth Humans alone represent a mass that is an order of magnitude greater than all wild mammals combined, and when you add in livestock, the domesticated-mammal total dwarfs wild mammalian life even further.
Ants at 12 megatons of dry carbon sit somewhere in the neighborhood of 0.6 percent of all animal biomass, which sounds small until you realize that is one family of insects outweighing all wild birds and wild mammals put together. In terms of sheer ecological footprint per unit of evolutionary lineage, ants punch far above their weight.
Among their fellow soil-dwelling arthropods, though, ants are not even the heaviest hitters. A 2023 estimate of global terrestrial arthropod biomass found roughly 200 megatons of dry biomass in the soil, with termites contributing about 40 percent and ants only about 10 percent.10PubMed Central. The global biomass and number of terrestrial arthropods Soil mites and springtails account for the vast majority of individual soil arthropods by count, though not by mass. Termites, it turns out, are the real heavyweight social insects in the soil, outweighing ants by a factor of about four underground.
What All That Ant Mass Does to the Planet
Twenty quadrillion ants are not just sitting there. Their collective activity reshapes soil structure, nutrient cycles, and even greenhouse gas emissions. A 2026 meta-analysis of ant effects on soil carbon cycling found that ant nesting activities increased soil organic carbon storage by an average of 22 percent in the soil immediately around nests, compared to nearby reference soil. At the same time, those nests boosted carbon dioxide emissions by 84 percent, effectively turning ant colonies into localized hotspots of greenhouse gas release.11PubMed Central. A meta-analysis of ant-mediated effects on soil carbon cycling and organic matter stability Ant nests also stimulated nitrous oxide emissions, though their effect on methane flux was unclear.
The mechanisms behind this are straightforward. Ants excavate tunnels and chambers, mixing soil layers and bringing organic material down into their nests. Different species have different effects. Research in a tropical forest in Xishuangbanna found that microbial biomass carbon, total organic carbon, total nitrogen, and ammonium were all higher in ant nests than in surrounding soil, but the magnitude depended on what the ants ate and how they built.12Soil Biology and Biochemistry. Ants can exert a diverse effect on soil carbon and nitrogen pools in a Xishuangbanna tropical forest Predatory ants, herbivorous ants, and fungus-farming ants each leave a different chemical signature in their nest soil.
As soil movers, ants are significant but not dominant everywhere. In cold-temperate European ecosystems, earthworms generally outperform ants as bioturbators, the organisms responsible for physically churning soil. Ants moved between 0.2 and 1 megagram of dry soil per hectare per year in those environments, and only surpassed earthworms in very acidic forest soils where earthworms struggled.13Ecosystems. Ant and Earthworm Bioturbation in Cold-Temperate Ecosystems In tropical soils, the balance shifts more toward ants and termites, partly because tropical ant biomass density is so much higher.
Invasive Ants and Ecological Dominance
When the biomass comparison gets weird is at the local scale. In certain invaded ecosystems, a single ant species can reach densities so extreme that it restructures the entire food web. On Christmas Island in the Indian Ocean, yellow crazy ants formed supercolonies that reduced other ant species richness, occupied the burrows of the island’s famous red crabs, and killed the crabs in numbers large enough to trigger what ecologists call an “invasional meltdown,” a cascading collapse of the native ecosystem driven by one invader.14Diversity and Distributions. Spatial dynamics of supercolonies of the invasive yellow crazy ant, Anoplolepis gracilipes, on Christmas Island, Indian Ocean
These kinds of local explosions are a reminder that global biomass averages can obscure the reality on the ground. In a patch of tropical forest or an oceanic island overrun by a supercolony, the local ant biomass per square meter can be extraordinary, easily dwarfing the mass of all other animals in that patch. The global comparison to humans is a fun thought experiment, but the ecological story is really about how concentrated ant mass drives outsized effects in specific places.
How Climate Change Could Shift the Balance
The ratio between ant biomass and human biomass is not fixed. On the human side, population continues to grow, and average body mass is still increasing in most countries. On the ant side, the trajectory is less clear. A 20-year study of ant communities found that colony abundance initially increased as temperatures rose by up to 1°C, then declined as warming exceeded that threshold, with some sites experiencing mean monthly temperature changes of up to 2.4°C.15PubMed. Species energy and Thermal Performance Theory predict 20-yr changes in ant community abundance and richness Ant abundance also tracked changes in net aboveground productivity, the amount of plant material available to support the food web.
Broader insect decline trends add another layer of uncertainty. Evidence across multiple insect taxa points to decreasing biomass in many regions, driven by habitat loss, pesticide use, and climate disruption.16Austral Entomology. Further evidence for a global decline of the entomofauna Whether ants are declining at the same rate as other insects is hard to say. Their colonial lifestyle, underground nesting, and dietary flexibility may buffer them somewhat. But if global ant populations do shrink while human biomass continues expanding, the already-lopsided comparison will become even more so.
How Ants Got This Successful in the First Place
Ants have been around for over 100 million years, but their rise to ecological dominance is tied to a more specific event. Research into the macroecological diversification of ants suggests that most early ant lineages lived in forested habitats until the middle-to-late Paleogene and early Neogene, when several groups independently evolved preferences for non-forested, open habitats and continued diversifying through the Neogene.17PubMed Central. Macroecological diversification of ants is linked to angiosperm evolution The rise of flowering plants, which transformed global ecosystems by creating new food sources and habitat structures, appears to have been a key enabler of ant diversification. The sugar-rich secretions produced by flowering plants and the aphids that feed on them gave ants a high-energy fuel source that supported the large colony sizes we see today.
This evolutionary history matters for the biomass question because it underscores that ants have had tens of millions of years to fill ecological niches across the planet. Humans, by contrast, have achieved our current biomass in the blink of an evolutionary eye, mostly in the last 200 years. The ants’ 20 quadrillion individuals represent an ancient, slow-built dominance. Ours represents a recent, explosive one driven by agriculture and fossil energy. Both are remarkable, but they got there by completely different routes and on completely different timescales.