Ants are among the most widespread and diverse insect groups on Earth, inhabiting nearly every terrestrial environment. These social insects play various roles in their ecosystems, from tiny scavengers to significant earth movers. The sheer number of ants across the planet is a topic of ongoing scientific inquiry, prompting questions about their global population size and collective influence.
The Staggering Ant Population
A recent comprehensive study estimates a truly immense number of ants on Earth. Researchers calculated that there are approximately 20 quadrillion individual ants globally. This figure is significantly higher than previous estimations.
To put this into perspective, this means there are roughly 2.5 million ants for every human on the planet. The collective dry biomass of these ants is estimated to be about 12 megatons of carbon. This total mass surpasses the combined biomass of all wild birds and mammals, equating to around 20% of humanity’s total biomass.
Estimating the Earth’s Ant Population
Determining the exact number of ants on Earth presents considerable challenges due to their small size, diverse habitats, and often subterranean lifestyles. Scientists, however, have developed sophisticated methodologies to arrive at these large-scale estimates. A recent study, published in the Proceedings of the National Academy of Sciences, employed a “bottom-up” approach, unlike earlier broad estimates.
This rigorous approach involved compiling data from 489 studies conducted by ant scientists worldwide. These studies spanned all continents, excluding Antarctica, and covered major biomes and habitats, including forests, deserts, grasslands, and urban areas. Researchers used standardized methods for collecting and counting ants, such as pitfall traps and leaf litter sampling, to gather empirical evidence from field observations.
The compiled data allowed researchers to quantify ant density in various parts of the globe. They then extrapolated these local densities to estimate populations across different biomes and habitat types. While the estimate of 20 quadrillion ants is considered conservative, researchers acknowledge that certain populations, such as those living entirely underground, are harder to account for and might lead to even higher figures. The uneven distribution of ants, with tropical regions generally harboring more individuals, was also factored into these calculations.
The Ecological Importance of Ants
Ants play various roles within ecosystems, influencing soil health, nutrient cycling, and plant distribution. Their constant tunneling activities help to aerate the soil, creating channels that allow water and oxygen to penetrate deeper, which benefits plant roots and improves overall soil structure.
Ants are also instrumental in nutrient cycling by bringing organic matter, such as dead insects and decaying plant material, into their nests. This process breaks down organic debris, enriching the soil with essential nutrients.
Ants are important seed dispersers (myrmecochory) for many plant species. They are attracted to nutrient-rich appendages on seeds, called elaiosomes, which they carry back to their nests. After consuming the elaiosome, ants discard the seed in nutrient-rich areas, aiding germination and plant colonization.
Beyond these roles, ants act as both predators and prey, helping to regulate insect populations, including many agricultural pests, and serving as a food source for numerous other animals, from birds to amphibians.