Our planet teems with life, much of it unseen. Among the most pervasive and successful inhabitants are ants, tiny insects found across nearly every terrestrial environment, from scorching deserts to lush rainforests. These highly organized creatures showcase an astonishing diversity in form and function. Their omnipresence hints at their vast numbers and significant impact on Earth’s ecosystems.
The Global Ant Population
Recent scientific analysis provides a clearer picture of the immense number of ants inhabiting the Earth. A 2022 study published in the Proceedings of the National Academy of Sciences (PNAS) estimated 20 quadrillion individual ants globally. For every human on the planet, there are approximately 2.5 million ants. This estimate highlights the numerical dominance of these insects in terrestrial environments.
Estimating Ant Numbers
Accurately counting such an enormous and widespread population presents a scientific challenge. Scientists use a “bottom-up” estimation approach, relying on empirical data collected from the field. The 2022 PNAS study reviewed data from 489 ant population studies across all continents and major biomes. Researchers used standardized sampling methods, primarily pitfall traps (for ground-active ants) and leaf litter sampling (for forest floor ants). Density data from these localized samples were extrapolated across similar global habitats, with adjustments for un-sampled areas like forest canopies and subterranean networks.
Why Ants Are So Abundant
Ants owe their abundance to biological and ecological advantages. Their highly organized social structure, known as eusociality, allows for large, efficient colonies with specialized tasks, leading to collective success. Ants exhibit adaptability, thriving in nearly all ecosystems, including forests, grasslands, and urban areas. Their efficient foraging strategies enable them to exploit a wide range of food sources, contributing to their numbers. Ants also play a multifaceted role in ecosystems, acting as soil aerators, seed dispersers, and decomposers of organic matter, which facilitates nutrient cycling.
The Collective Weight of Ants
Beyond their vast numbers, the collective mass of all ants on Earth highlights their ecological significance. Scientists estimate the total dry weight, or biomass, of the global ant population to be approximately 12 megatons of carbon. This figure exceeds the combined biomass of all wild birds and mammals. The collective dry weight of ants is roughly equivalent to 20% of the total human biomass. This comparison illustrates why biologist Edward O. Wilson referred to ants as “the little things that run the world”.