How Many Ants Are There in the World? 20 Quadrillion Estimate

The 20 quadrillion estimate

The figure comes from a study by Patrick Schultheiss, Sabine Nooten, Benoit Guénard and colleagues at the University of Hong Kong and other institutions, published in the Proceedings of the National Academy of Sciences in 2022.

The team gathered data from 489 earlier studies on every continent where ants live, covering forests, grasslands, deserts and towns. These studies had counted ants with standard methods, such as pitfall traps sunk into the ground and samples of leaf litter. From the densities in each habitat and the area of each habitat on Earth, the researchers estimated the global total.

They concluded that ground-dwelling ants alone number more than 3 quadrillion, and that all ants, including those in trees and soil, number almost 20 quadrillion. The authors called this a conservative estimate, because many habitats, especially soil and treetops, are hard to sample.

How heavy are all the ants?

The study also estimated the total biomass of ants, measured as dry carbon, the standard way biologists compare living things. All ants on Earth contain about 12 megatons (12 million tonnes) of carbon.

An older idea, popularized by the famous ant scientist E. O. Wilson, was that all the ants on Earth together weigh about as much as all humans. Wilson’s estimate assumed 1 to 10 quadrillion ants. The 2022 study found more ants but suggests their total biomass is about a fifth of humanity’s.

Where do most ants live?

Ants live on every continent except Antarctica. Only a few cold or isolated islands, such as Iceland and Greenland, have no native ants.

The study found that ground-dwelling ants are most abundant in tropical and subtropical regions. Tropical forests and savannas hold the most ants, with numbers dropping toward the poles. Within habitats, the densest populations of leaf-litter ants were in forests, while dry regions had the highest numbers of ants foraging on the ground surface.

Local numbers can be astonishing. A single colony of the red wood ant in a European forest can hold 100,000 to 400,000 workers, and a mature leafcutter ant nest in Central America may contain several million. You can read more in how big are leafcutter ant colonies?

How many ant species are there?

About 14,000 species of ants have been formally named and described, in more than 300 genera. Experts estimate that the true number could be 20,000 or more, with many species still undiscovered, especially in tropical forests and soil.

Ant species range in size from tiny workers less than 1 mm long to the giant bullet ants and bulldog ants of the tropics and Australia, which can exceed 2.5 cm (1 in). The richest ant faunas are in tropical South America, Africa and Southeast Asia. Europe has a few hundred species, and the United States and Canada together have roughly 1,000.

Why are there so many ants?

Ants have been around for more than 100 million years, since the age of dinosaurs. Several features helped them spread across the planet.

• Teamwork. Living in colonies lets ants share work, defend territory and take on prey much larger than themselves. Communication by smell coordinates thousands of workers; see how do ants communicate?
• Flexible diets. Most ants are omnivores that eat insects, seeds, honeydew, nectar and scraps. Some farm fungi or herd aphids.
• Partnerships. Many plants feed or house ants in return for protection or seed dispersal.
• Small size. Ants can exploit tiny spaces in soil, litter and wood, where few large animals can reach.

Why it matters to count ants

Ants are among the most important animals on land. They turn and aerate soil, recycle dead material, spread seeds, prey on other insects and are food for many birds, lizards and mammals, including specialists such as anteaters and pangolins. Counting them gives scientists a baseline to track changes as insects face habitat loss and climate change.

The 2022 study also highlighted gaps. Large parts of Africa and Asia have few ant surveys, and treetops and deep soil are poorly sampled, so the true number of ants could be higher still.

Myths and facts

Myth: All ants weigh the same as all humans. Fact: This idea is outdated. The best current estimate puts ant biomass at about 20% of human biomass, though still more than wild birds and mammals combined.

Myth: Ants are found everywhere on Earth. Fact: Antarctica and some cold islands have no native ants.