Roughly 20 quadrillion ants live on Earth, according to the most rigorous estimate to date. That number, published in 2022, drew on nearly 500 studies spanning every continent and major habitat type, and came out to about 20 × 1015 individuals. To put that in perspective, it means there are about 2.5 million ants for every person alive. The figure is staggering, but the story behind it, and what it means for the planet’s ecosystems, is just as striking.
Where That Number Comes From
Before 2022, estimates of the global ant population were essentially educated guesses, often circling around one quadrillion or so without much empirical grounding. The landmark study that changed this compiled data from 489 individual field studies conducted across all continents, major biomes, and habitat types. The researchers separated their analysis into ground-dwelling ants and arboreal (tree-dwelling) ants, because the two groups require very different counting methods and occupy fundamentally different ecological niches. Ground-dwelling ants alone numbered over 3 quadrillion. When arboreal ants were included, the total climbed to nearly 20 quadrillion, a figure the authors described as conservative.1PubMed Central. The abundance, biomass, and distribution of ants on Earth
That conservatism matters. Counting ants is not like counting elephants. You cannot survey them from aircraft or tag them with GPS collars. Researchers rely on ground-level methods like pitfall traps, which are small cups sunk into the soil that passively capture crawling insects, and Winkler extractors, which use mesh bags to sift ants out of leaf litter samples. Each method has blind spots. Pitfall traps tend to catch more species overall and provide a more complete picture of species diversity than bait traps, which attract ants to food sources and can oversample aggressive, fast-recruiting species.2Journal of Economic Entomology. A Comparison of Pitfall Traps with Bait Traps for Studying Leaf Litter Ant Communities Meanwhile, Winkler extraction provides reliable data on leaf litter ant communities, though it can slightly undercount ants when the litter is very moist.3Journal of Insect Science. Influence of leaf litter moisture on the efficiency of the Winkler method for extracting ants
Because no single method captures every ant in every habitat, the global estimate was built by aggregating density measurements from local studies and then scaling up across known habitat areas. Tropical forests, savannas, temperate woodlands, deserts, and urban areas all contributed data, though coverage was uneven. Some regions, particularly large swaths of central Africa and central Asia, had relatively few studies. This is one reason the researchers emphasized their figure was a lower bound rather than a midpoint estimate.
How Ant Populations Compare to Other Life on Earth
Twenty quadrillion is a number that resists intuition, so biomass offers a more tangible comparison. The global ant population represents roughly 12 megatons of dry carbon. That exceeds the combined biomass of all wild birds and all wild mammals on the planet, and amounts to about a fifth of total human biomass.1PubMed Central. The abundance, biomass, and distribution of ants on Earth In other words, if you weighed every wild deer, whale, eagle, and sparrow together, the ants would still outweigh them.
Even within the arthropod world, ants punch above their weight. A separate global assessment of terrestrial arthropods estimated the total number of soil-dwelling arthropods at around 10 quintillion individuals. Mites and springtails account for more than 95 percent of those by sheer headcount. By biomass, however, ants claim roughly 10 percent of the soil arthropod total, on par with springtails and mites individually. Termites, their closest ecological rivals, contribute about 40 percent of soil arthropod biomass.4PubMed Central. The global biomass and number of terrestrial arthropods So while ants are far outnumbered by microscopic soil creatures, their individual body size means they move a disproportionate amount of material and energy through ecosystems.
Where Most Ants Live
Ant density is wildly uneven around the globe. Tropical and subtropical forests harbor the highest concentrations by a wide margin. These warm, humid environments produce the deep leaf litter layers and complex vegetation structures that support enormous ant populations. In an Amazonian rainforest study, researchers documented 494 ant species across three vertical layers: ground and litter, understory, and canopy. The vast majority of species, 357 out of 494, lived on the ground or in the leaf litter. The canopy hosted a smaller but distinct community of specialists, and the understory had its own set of species tied to specific plant associations.5PubMed Central. Ant Diversity and Stratification in an Amazonian Rainforest This vertical layering means that even a single hectare of tropical forest can contain dozens of separate ant communities stacked on top of one another, driving up both diversity and total abundance.
At the other extreme, arid environments support far fewer ants but are not devoid of them. In a Gobi Desert study, researchers found that ant activity tracked temperature and rainfall closely, with the monthly catch of ants rising and falling in sync with both precipitation and mean monthly temperature. Average abundance was about 19 individuals per trap per year, dominated by seed-harvesting species.6ScienceDirect (Research in Cold and Arid Regions). Spatial and temporal distribution patterns of ants (Hymenoptera: Formicidae) in Gobi Desert ecosystems, Northwest China That is a tiny fraction of what a tropical forest plot would yield, but desert ants have evolved remarkable physiological adaptations to tolerate heat stress, long foraging distances, and scarce food. Their contribution to global numbers is small, but their ecological role in those dry systems is outsized.
Cities represent a third, increasingly important habitat. Only a small subset of the world’s ant species consistently thrives in urban environments. Research into what has been called an “urban ant syndrome” finds that the ants succeeding in cities share a recognizable toolkit: they form sprawling colonies with multiple nests, they reproduce by budding rather than risky mating flights, they tolerate the heat island effect that makes cities warmer than surrounding countryside, and they shift their diets toward human-derived sugary foods or mutualisms with sap-feeding insects on ornamental plants.7PubMed. Pathways to city dominance: the urban ant syndrome In heavily urbanized areas, a handful of these species can dominate at extraordinary densities, even if total species diversity drops.
What Ants Do at That Scale
The sheer volume of ants on Earth means their collective activities reshape ecosystems in ways that few other organisms can match. Three roles stand out.
First, ants are prolific earth movers. By excavating nests, carrying soil particles to the surface, and rearranging organic material underground, ants turn over enormous quantities of soil. In semi-arid Australian habitats, researchers measured bioturbation rates of ant communities at 10 to 37 grams per square meter per year on average, with one especially active species, an Aphaenogaster ant, moving hundreds of grams per square meter per year on its own.8Australian Journal of Soil Research. The bioturbation activity of ants in agricultural and naturally vegetated habitats in semiarid environments Multiply those rates across the landscapes where ants are abundant, and the cumulative soil mixing rivals that of earthworms in many regions. This tunneling aerates compacted ground, improves water infiltration, and redistributes nutrients from deep soil layers to the surface.
Second, ants are important seed dispersers. Many plant species produce seeds with a fleshy, oil-rich appendage called an elaiosome, specifically to attract ants. The ants carry the seed back to the nest, feed the elaiosome to their larvae, and discard the intact seed in the nutrient-rich refuse pile, effectively planting it in a fertilized, protected spot. Research from a temperate grassland found that ant-mediated dispersal substantially increased the distance seeds traveled compared to seeds simply falling from the parent plant, and ants even moved some seeds from species that lack the specialized elaiosome.9PubMed Central. Evaluation of seed-dispersal services by ants at a temperate pasture: Results of direct observations in an ant suppression experiment In some ecosystems, particularly Southern Hemisphere shrublands and temperate deciduous forests, ants are the primary seed-dispersal agents for dozens of plant species.
Third, ants regulate other insect populations through predation. Ant colonies are voracious consumers of small invertebrates, and their collective hunting pressure can suppress pest populations in agricultural settings. Weaver ants, for instance, have been used as biological pest control in fruit orchards for centuries in parts of Southeast Asia. At the global scale, ants’ predatory activity helps hold herbivorous insect populations in check, which in turn influences plant growth and forest structure.
Supercolonies and the Invasion Problem
Most ant species live in discrete colonies with a single queen or a small number of queens, and colonies defend territories against neighbors of the same species. But a few species have broken free of that model entirely. The Argentine ant, originally from South America, forms what are called supercolonies: genetically similar populations spread over vast distances in which workers from different nests show no aggression toward one another. In southern Europe, one Argentine ant supercolony stretches over 6,000 kilometers from Italy to the Spanish Atlantic coast, making it the largest known cooperative unit of any animal on Earth.10PubMed Central. Evolution of supercolonies: the Argentine ants of southern Europe
Supercoloniality is a major reason some ant species become devastating invaders. When workers from neighboring nests cooperate rather than fight, the colony can pour all its energy into growth and food acquisition instead of territorial defense. About 23 ant species are recognized as invasive worldwide, and their ecological damage follows a consistent pattern: they outcompete native ants for food and nesting sites, prey on native invertebrates, and disrupt relationships between plants and their native pollinators or seed dispersers.11PubMed. Impact of invasive ant species on native fauna across similar habitats under global environmental changes
Among invasive species, the Argentine ant and the big-headed ant are especially formidable competitors. In experimental trials comparing four widespread invasive species, these two discovered food baits fastest, recruited the most workers, and dominated food resources most effectively.12PubMed Central. Discovery–dominance trade-off among widespread invasive ant species Their speed and numbers let them monopolize resources before native species even arrive. On islands and in other isolated ecosystems, this competitive dominance can lead to the local extinction of native ant species and cascading losses up the food chain as lizards, birds, and other animals that depend on native ants lose their prey base.
The global ant count does not distinguish between native and invasive populations, so it is worth noting that invasive ants can locally inflate ant density while simultaneously reducing species diversity. A Hawaiian island overrun by the big-headed ant may have more individual ants per square meter than it did before the invasion, but far fewer species. The headline number of 20 quadrillion tells you about quantity, not ecological health.
How Climate Change Could Shift the Count
A warming planet will not affect all ants equally. A synthesis of research on ant responses to climate change found that species living in the tropics, and particularly those in thermally variable microhabitats like the canopy or leaf litter layer, are expected to suffer as temperatures rise. Many tropical ant species already live close to their thermal limits, so even modest warming can push them past the point where they can forage or reproduce effectively. Meanwhile, ants in temperate zones, and species able to buffer their nest temperatures by nesting underground, may be unaffected or could even benefit from milder winters and longer warm seasons.13PubMed Central. The response of ants to climate change
This creates a likely geographic reshuffling rather than a simple global increase or decrease. Tropical forests, which currently hold the largest share of the global ant population, could see declines in both diversity and abundance. Temperate and boreal regions could see gains as some species expand their ranges poleward. The net effect on the total count is genuinely uncertain. It depends on whether tropical losses outpace temperate gains, and on how habitat destruction interacts with temperature changes. Deforestation in the tropics is already reducing ant habitat faster than climate change alone would, so the two pressures compound.
For desert-dwelling ants, the picture is mixed. Their activity already tracks moisture and temperature closely, so shifting rainfall patterns could either open new foraging windows or close existing ones depending on the region. The Gobi Desert data showing a tight correlation between monthly ant catches and both precipitation and temperature hint at how sensitive these populations are to even small climatic shifts.6ScienceDirect (Research in Cold and Arid Regions). Spatial and temporal distribution patterns of ants (Hymenoptera: Formicidae) in Gobi Desert ecosystems, Northwest China
How Ants Became So Dominant in the First Place
Ants have been around for well over 100 million years, but they were not always so numerous. Fossil evidence and phylogenetic analyses suggest that the initial ant radiation took place in the mid-Cretaceous period, when ants diversified in forest ground litter and soil alongside the rise of flowering plants. It was during a later wave, in the Paleogene period roughly 40 to 60 million years ago, that ants achieved something closer to their modern ecological dominance, again in tandem with the expansion of angiosperm-dominated tropical forests.14PubMed Central. The rise of the ants: a phylogenetic and ecological explanation The implication is that the extraordinary ant numbers we see today are not a fixed feature of life on Earth. They are the product of a specific co-evolutionary relationship with flowering plants that built the complex forest ecosystems where ants thrive.
That relationship runs deep. Flowering plants provide the leaf litter ants nest in, the fruits and seeds they eat and disperse, and the nectar and honeydew (via sap-sucking insects) that fuels the sugar-hungry metabolisms of large colonies. In return, ants aerate the soil around plant roots, disperse seeds, and protect plants from herbivores. Remove the forests, and you lose the ants. The current global estimate of 20 quadrillion is inseparable from the current extent and health of the world’s forests. As those forests change, whether through logging, agriculture, or climate-driven shifts in vegetation, the ant count will change with them.
There are now more than 14,000 described ant species, with new species still being identified regularly, particularly in tropical canopies and subterranean habitats that remain undersampled. The true species count is almost certainly higher. Each species fills a slightly different ecological niche, from fungus-farming leafcutter ants in the Neotropics to nomadic army ants that raid other insect colonies, to tiny, nearly invisible soil ants that process decaying organic matter. That diversity is the engine behind the big number. Twenty quadrillion ants are not twenty quadrillion copies of the same creature. They represent thousands of species, each adapted to a particular slice of the terrestrial world, collectively filling roles that no other group of organisms could replace.