How Many Ants Are in the World? Estimating the Global Ant Population

The most rigorous scientific estimate to date places the global ant population at nearly 20 quadrillion individuals, or approximately 20 × 10¹⁵ ants. This figure comes from a 2022 synthesis published in the Proceedings of the National Academy of Sciences that compiled data from 489 studies across all continents, major biomes, and habitats. The same analysis estimated that ground-dwelling ants alone number over 3 × 10¹⁵ individuals, with the total ant biomass reaching roughly 12 megatons of dry carbon. For context, this exceeds the combined biomass of wild birds and mammals and equals about 20 percent of human biomass. This article explains how scientists arrived at these numbers, what methods they used, and why ant abundance matters for understanding terrestrial ecosystems.

At a Glance: Key Figures on Global Ant Abundance

The table above summarizes the headline numbers from the most comprehensive global ant census attempted to date. Each figure carries uncertainty, and the researchers describe their estimates as conservative for ground-dwelling ants. The 20 quadrillion total includes arboreal ants, which are harder to sample and therefore less well represented in the underlying studies.

Why Counting Ants Matters for Ecological Science

Knowledge about the distribution and abundance of organisms is fundamental to understanding their roles within ecosystems and their ecological importance for other taxa. This principle, stated in the 2022 PNAS study, explains why scientists have invested substantial effort in estimating ant numbers. Ants have long been regarded as the "little things that run the world" because of their influence on soil structure, nutrient cycling, seed dispersal, and predation across nearly every terrestrial habitat.

For farmers and land managers, ant abundance is not an abstract curiosity. Ants affect crop pest populations, soil aeration, organic matter decomposition, and the establishment of plants through seed dispersal. Understanding baseline ant populations helps in distinguishing normal ecological variation from the effects of land-use change, pesticide application, or invasive species establishment.

The 2022 study also highlights a critical gap: reliable estimates of insect abundance have been lacking even for ubiquitous groups like ants. This absence of baseline data makes it difficult to track how insect populations respond to environmental change. The new global estimate provides a crucial baseline for exploring environmental drivers of ant-abundance patterns and for monitoring the responses of insects to environmental change over time.

Methods Used to Estimate Global Ant Numbers

Compiling Data from Published Studies

The 2022 PNAS analysis did not involve new field sampling. Instead, the researchers compiled existing data from 489 studies that had measured ant abundance in specific locations. These studies spanned all continents, major biomes, and habitat types, providing broad geographic coverage. Each study contributed data on either ground-dwelling ants, arboreal ants, or both.

The distinction between ground-dwelling and arboreal ants matters for estimation accuracy. Ground-dwelling ants are typically sampled using pitfall traps, leaf-litter extraction, or soil core sampling. Arboreal ants require different methods, such as canopy fogging or branch sampling, which are logistically harder and less frequently performed. This sampling gap means arboreal ant abundance estimates carry more uncertainty.

Estimating Abundance from Density Measurements

The researchers converted site-level density measurements into global abundance estimates by extrapolating across habitat types and geographic regions. They calculated the number of ants per unit area for different habitats, then multiplied these densities by the global extent of each habitat. This approach requires assumptions about how representative individual study sites are of broader habitat categories.

For ground-dwelling ants, the analysis produced a conservative estimate of over 3 × 10¹⁵ individuals. The word conservative reflects the researchers' choice to use lower-bound density values where data were sparse or variable. The total estimate of nearly 20 × 10¹⁵ individuals includes arboreal ants and uses the full range of available density data.

Converting Abundance to Biomass

Biomass estimates require converting individual ant counts into carbon mass. The researchers applied per-individual carbon content values to the abundance estimates, yielding approximately 12 megatons of dry carbon for the global ant population. This biomass figure allows direct comparison with other animal groups.

The comparison to human biomass is striking. At roughly 20 percent of human biomass, ants represent a substantial portion of the world's animal carbon. The comparison to wild birds and mammals is equally notable: ants outweigh both groups combined. These comparisons help non-specialists grasp the ecological scale of ant populations.

Habitat Patterns in Ant Abundance

Tropical and Subtropical Concentration

Ant abundance is strongly concentrated in tropical and subtropical regions. The 2022 PNAS analysis found that ground-dwelling ant densities are highest in these zones, although abundance varies substantially across habitats even within the same latitude. This geographic pattern aligns with broader biodiversity gradients, where species richness and abundance typically peak near the equator.

For researchers studying ant ecology, this concentration means that global estimates are sensitive to how well tropical regions are represented in the underlying data. Gaps in tropical sampling could bias global estimates downward, since these regions likely harbor higher ant densities than temperate zones.

Forest Leaf-Litter Ants

The density of leaf-litter ants is highest in forests. Leaf-litter habitats provide stable moisture, temperature, and food resources that support dense ant communities. Forest floors in tropical and subtropical regions can support remarkable numbers of ants per square meter, and these habitats contribute disproportionately to global ant abundance.

Forest management decisions directly affect leaf-litter ant communities. Timber harvest, slash-and-burn agriculture, and conversion of forest to other land uses remove or degrade leaf-litter habitats. The 2022 study's finding that forest leaf-litter ant densities are highest in forests underscores the conservation value of maintaining forest cover for ant biodiversity.

Arid Region Ground-Foraging Ants

The numbers of actively ground-foraging ants are highest in arid regions. This pattern may seem counterintuitive given the lower overall productivity of arid ecosystems, but desert and semi-arid ant communities are often dominated by highly active foraging species that are well sampled by pitfall traps. These ants play important roles in seed dispersal and soil turnover in water-limited environments.

For land managers in arid regions, this finding suggests that ant activity observed on the surface may not reflect total ant abundance. Many arid-region ants are nocturnal or avoid extreme temperatures, so surface activity patterns vary seasonally and daily.

Ecological Significance of Ants

Ants as Ecosystem Engineers

Ants modify their environments in ways that affect other organisms. Their nest construction aerates soil, improves water infiltration, and concentrates organic matter. These activities influence plant growth, soil microbial communities, and the abundance of other soil invertebrates. The sheer number of ants globally means these engineering effects operate at landscape scales.

In agricultural systems, ant nests can improve soil structure in ways that benefit crop roots. However, some ant species protect honeydew-producing insects like aphids, which can increase pest damage to crops. Farmers must weigh these competing effects when making management decisions.

Ant-Mediated Seed Dispersal

Myrmecochory, the dispersal of seeds by ants, is a significant ecological interaction. Ants carry seeds to their nests, where the seeds may germinate in nutrient-rich conditions or escape seed predators. This interaction is particularly important in fire-prone and nutrient-poor ecosystems, where ant-dispersed plants are common.

A 2026 ecological synthesis on myrmecochory notes that the wide distribution and high biomass of ants mean this dispersal mechanism can strongly influence plant dispersal patterns. The same synthesis warns that invasive ants could threaten myrmecochory by displacing native ant species, increasing seed predation, and facilitating the dispersal of invasive plants. Urban heat island effects and habitat fragmentation could also disturb the dispersal, germination, and growth of myrmecochorous plants.

Ants in Food Webs

Ants occupy multiple trophic levels in terrestrial food webs. Many species are predators of other invertebrates, while others consume seeds, nectar, honeydew, or fungi. This dietary diversity means ants influence prey populations, plant reproduction, and the abundance of other predators that feed on ants.

The 2022 PNAS study's finding that ant biomass exceeds that of wild birds and mammals highlights the central role ants play in terrestrial ecosystems. Birds and mammals that consume ants benefit from this abundant food resource, and plants that depend on ant predation for protection from herbivores rely on ant activity for survival.

Practical Assessment: Measuring Ant Abundance on Your Land

Selecting Sampling Methods

Land managers who want to assess ant populations on their property can choose from several standard methods. Pitfall traps capture ground-foraging ants and are simple to deploy. Leaf-litter extraction, using a Berlese funnel or Winkler sack, samples ants living within the litter layer. Soil core sampling captures subterranean ants. Each method captures a different subset of the ant community, so multiple methods provide a more complete picture.

The 2022 PNAS study relied on all of these methods across its 489 source studies. For a single property assessment, pitfall traps are the most practical starting point because they require minimal equipment and provide comparable data across sites.

Establishing Sampling Plots

To assess ant abundance systematically, establish multiple sampling plots that represent the range of habitats on your land. For each plot, deploy pitfall traps in a grid pattern, leaving them active for a standard period such as 48 hours. Identify ants to at least the genus level and count individuals per trap. Repeat sampling across seasons to capture temporal variation in ant activity.

Record the following data for each sampling event: date, location, habitat type, weather conditions, trap count, and ant count per trap. This record allows you to track changes in ant abundance over time and to compare sites within your property.

Interpreting Results

Ant abundance varies naturally across seasons and habitats. A single sampling event provides a snapshot, not a definitive population estimate. Compare your results with regional reference data if available, and look for consistent patterns across multiple sampling events before drawing conclusions.

If you observe dramatic declines in ant abundance following pesticide application or habitat disturbance, investigate potential causes. Ant populations can recover if the underlying stressor is removed, but chronic disturbance may prevent recovery.

Records and Measurements for Ant Monitoring

Maintain these records in a consistent format across years. Long-term records are more valuable than single-season snapshots because they reveal trends that short-term observations miss.

Common Failure Patterns in Ant Abundance Assessment

Sampling Bias from Method Choice

Pitfall traps capture active foragers but miss ants that remain in nests or forage in the canopy. Leaf-litter extraction misses ground-foraging ants that do not inhabit the litter layer. Relying on a single method produces biased estimates that do not reflect total ant abundance. The 2022 PNAS study addressed this by compiling data from multiple methods, but individual assessments often lack this breadth.

Seasonal and Weather Effects

Ant activity varies with temperature, moisture, and time of day. Sampling during a cold snap or drought will produce low counts that do not reflect true abundance. Standardize sampling conditions where possible and record weather data to interpret results correctly.

Invasive Species Distortion

Invasive ants can dominate samples and obscure native ant communities. The Argentine ant, Linepithema humile, is one of the world's worst invasive species, with established populations in at least 40 countries on six continents. Research on this species shows that its invasion can reduce native ant richness by eliminating refugia for native ants in fragmented habitats. If your samples are dominated by a single non-native species, native ant abundance may be underestimated.

Incomplete Taxonomic Identification

Identifying ants to species requires specialized knowledge and often microscopic examination. Many land managers identify ants only to family or genus level, which limits the ecological conclusions that can be drawn. If species-level identification is needed, consider sending samples to a taxonomic specialist or using regional identification guides.

Limitations of Current Global Estimates

Geographic and Ecological Gaps

The 2022 PNAS study acknowledges major ecological and geographic gaps in current knowledge. Some regions and habitats remain undersampled, particularly tropical forests and subterranean ant communities. These gaps introduce uncertainty into global estimates, and the true number of ants on Earth could be higher than the current estimate.

Arboreal Ant Uncertainty

Arboreal ants are harder to sample than ground-dwelling ants, and the 2022 study's total estimate of nearly 20 × 10¹⁵ individuals includes substantial uncertainty from this group. Canopy sampling requires specialized equipment and access, so fewer studies have measured arboreal ant densities. The researchers note that their ground-dwelling estimate is conservative, suggesting that the true total may exceed the reported figure.

Temporal Variability

Ant populations fluctuate over time in response to weather, resource availability, and disturbance. The 489 studies compiled for the 2022 analysis were conducted over many years, and the global estimate represents an average condition instead of a fixed number. Long-term monitoring is needed to understand how ant abundance changes over time.

Invasive Species Effects

Invasive ants can dramatically alter local ant communities, as documented for the Argentine ant in coastal southern California. A 2021 study found that over 21 years, the area invaded by Argentine ants increased by 36.7 percent and their relative abundance increased by 121.95 percent in sampled fragments. At one fragment, native ground-foraging ant diversity declined from 14 to 4 species. Global estimates that include invaded sites may not reflect pre-invasion conditions.

Welfare and Safety Context for Ant Handling

Safe Observation Practices

Most ant species pose no threat to humans, but some can sting or bite. Fire ants, including Solenopsis invicta, are aggressive and their stings cause painful reactions. Research on potential global range expansion of the invasive fire ant indicates that this species may spread to new regions under changing climate conditions. When sampling ants, wear protective gloves and footwear, and avoid disturbing large nests of aggressive species.

Ethical Considerations

Ants are living organisms, and sampling methods that kill ants should be used judiciously. Pitfall traps typically kill captured ants, so limit sampling duration and number of traps to what is necessary for your assessment. If you are monitoring ant communities over time, consider using non-lethal observation methods where possible.

Regulatory Context

Some ant species are regulated as pests or invasive species. Movement of soil, plants, or equipment can spread invasive ants to new areas. If you suspect an invasive ant species on your property, contact your local agricultural extension service or invasive species authority for guidance. Do not attempt eradication without professional advice, as improper control can worsen infestations.

Professional Escalation Criteria

When to Seek Expert Help

Consult a professional entomologist or extension specialist if you observe any of the following: a dramatic decline in ant abundance that cannot be explained by weather or management changes, the appearance of an unfamiliar ant species that may be invasive, or ant-related damage to crops or structures that exceeds normal levels.

Invasive Species Suspicions

If you suspect the presence of a known invasive species such as the Argentine ant or fire ant, document the location and appearance of the ants, take photographs if possible, and contact your local invasive species authority. Early detection improves the chances of successful management.

Research Collaboration Opportunities

Researchers studying ant ecology may be interested in data from your property, particularly if you have long-term records. The 2022 PNAS study highlights major gaps in geographic and ecological coverage, and citizen-contributed data can help fill these gaps. Contact local universities or research institutions to explore collaboration opportunities.

Frequently Asked Questions

How did scientists count the number of ants in the world?

Scientists did not count every ant individually. Instead, they compiled data from 489 published studies that measured ant abundance at specific sites using methods like pitfall traps, leaf-litter extraction, and soil sampling. They then extrapolated these site-level density measurements across habitat types and geographic regions to produce a global estimate. The 2022 PNAS study used this approach to estimate nearly 20 × 10¹⁵ total ants and over 3 × 10¹⁵ ground-dwelling ants.

What is the ant to human ratio?

The 2022 PNAS study estimated ant biomass at approximately 12 megatons of dry carbon, which is about 20 percent of human biomass. In terms of individual numbers, the estimated 20 quadrillion ants vastly outnumber the approximately 8 billion humans on Earth. The ratio is roughly 2.5 million ants for every human, though this figure carries substantial uncertainty.

Why are there so many ants compared to other animals?

Ants are small, social, and highly efficient at exploiting resources. Their colony structure allows them to maintain large populations with relatively low per-individual energy costs. The 2022 PNAS study found that ant biomass exceeds the combined biomass of wild birds and mammals, reflecting the ecological success of this group across most terrestrial habitats.

How do scientists study ant populations?

Scientists study ant populations using several methods. Pitfall traps capture ground-foraging ants, leaf-litter extraction samples ants living in the litter layer, and soil cores capture subterranean ants. Canopy fogging samples arboreal ants. Each method captures a different subset of the ant community, so comprehensive studies use multiple methods. The 2022 PNAS study compiled data from all of these methods across 489 studies.

Are ant populations declining?

The 2022 PNAS study provides a baseline for tracking ant abundance over time, but it does not establish long-term trends. Some research suggests that invasive ants can cause local declines in native ant populations, as documented for the Argentine ant in California. However, global trends in ant abundance remain uncertain due to gaps in monitoring data.

What is the ecological importance of ants?

Ants influence soil structure, nutrient cycling, seed dispersal, and predation across terrestrial ecosystems. They are important predators of other invertebrates, mutualists with plants that produce extrafloral nectar, and dispersers of seeds through myrmecochory. The 2022 PNAS study highlights the central role ants play in terrestrial ecosystems and provides a baseline for understanding their ecological significance.

How do invasive ants affect native ant populations?

Invasive ants can displace native ants through competition, predation, and habitat modification. Research on the Argentine ant found that its invasion reduced native ant richness in fragmented habitats, with native species predicted to be sensitive to combined invasion and habitat loss disappearing from sampled sites. Invasive ants can also disrupt seed dispersal and other ecological interactions.

Can I measure ant abundance on my own property?

Yes, you can measure ant abundance using pitfall traps or other standard methods. Establish multiple sampling plots across different habitats, deploy traps for a standard period, and count and identify captured ants. Maintain consistent records across seasons and years to track changes over time. For species-level identification or suspected invasive species, consult a professional entomologist.

Related Articles

• Allergy Research Group
• Scientific Data Provenance For Reproducible Research
• Scientific Data Provenance For Reproducible Research
• Scientific Data Provenance For Reproducible Research
• Research Figures: Making Methods and Results Easier to Evaluate

References and Further Reading

• NCBI Literature Resources. National Center for Biotechnology Information.
• PubMed. National Library of Medicine.
• The abundance, biomass, and distribution of ants on Earth.. Proceedings of the National Academy of Sciences of the United States of America, 2022.
• Maternal nut and fish consumption during pregnancy and child risky decision-making at 11 years old.. European child & adolescent psychiatry, 2025.
• Prevalence and causes of vision loss in South-east Asia and Oceania in 2015: magnitude, temporal trends and projections.. The British journal of ophthalmology, 2019.
• Cardio-toxicity among patients with sarcoma: a cardio-oncology registry.. BMC cancer, 2020.
• Pervasive and persistent effects of ant invasion and fragmentation on native ant assemblages.. Ecology, 2021.
• Agreement between Ventilatory Thresholds and Bilaterally Measured Vastus Lateralis Muscle Oxygen Saturation Breakpoints in Trained Cyclists: Effects of Age and Performance.. Sports (Basel, Switzerland), 2024.
• Energy optimization and plant comfort management in smart greenhouses using the artificial bee colony algorithm.. Scientific reports, 2025.
• Forecasting alien species establishment and source regions: Quantitative assessment of potential ant invasions in Japan.. Ecological applications : a publication of the Ecological Society of America, 2025.
• A robust hybrid data driven approach to model biochar yield in terms of biomass pyrolysis.. 2026.
• Vulnerability of Myrmecochory to Anthropogenic Disturbances and Climate Change: An Ecological Synthesis.. 2026.
• Generalist rather than specialist ants drive the recovery of ant-mediated plant protection across secondary succession in a dry tropical forest. 2026.
• Chemical investigation of polycyclic aromatic hydrocarbon sources and associated health risks in PM&lt,sub&gt,2.5&lt,/sub&gt, from Eastern India.. 2026.
• The Argentine ant, Linepithema humile: natural history, ecology and impact of a successful invader. Entomologia generalis, 2024.
• Dominance hierarchies are a dominant paradigm in ant ecology (Hymenoptera: Formicidae), but should they be? and what is a dominance hierarchy anyways?. 2017.
• Wood Ant Ecology and Conservation. 2016.
• Future directions for wood ant ecology and conservation. 2016.
• Framing REDD+: political ecology, actor-network theory (ANT), and the making of forest carbon markets. Geographica Helvetica, 2023.
• The Fynbos and Succulent Karoo biomes do not have exceptional local ant richness. Plos One, 2012.
• Potential global range expansion of the invasive fire ant, Solenopsis invicta. Biological Invasions, 2004.
• Synergistic effect of habitat loss and chronic anthropogenic disturbances on ant species richness. Biodiversity and Conservation, 2024.
• A Surrogate-Assisted Continuous Ant Colony Optimization Method for Stochastic Optimization. 2025 IEEE Symposium for Multidisciplinary Computational Intelligence Incubators Mcii Companion 2025, 2025.

This article is educational and does not replace institutional policy, professional advice, or applicable safety and regulatory requirements.