To say that ants outnumber people on Earth would be a gross understatement. According to a new study, there are estimated to be 2.5 million times more ants on this planet than people.
In total, that's 20 quadrillion — or 20,000,000,000,000,000 — ants.
A team of researchers from Australia, Germany and Hong Kong analyzed 489 studies that gathered data on ground- and tree-dwelling ants in different habitats across all continents to come up with the mind-bending estimate. The research could help scientists understand the role that ants play in ecosystems and provide a way to assess how these insects and others are affected by threats such as climate change.
"Our results provide a crucial baseline for exploring environmental drivers of ant-abundance patterns and for tracking the responses of insects to environmental change," the scientists wrote in the study, which was published Monday in the journal Proceedings of the National Academy of Sciences.
The study also estimated that the total mass of ants on the planet works out to roughly 12 megatons of dry carbon, a huge sum that hints at their ubiquity, said Mark Wong, a Forrest Fellow in the School of Biological Sciences at the University of Western Australia.
Taken together, the total mass of ants on the planet would actually outweigh all of the world’s wild birds and mammals, he added.
"We found that there are literally tons of ants on Earth, which really underscores their ecological value," Wong said in a statement.
Ants can be found in nearly all habitats except for polar regions, according to the study. Forests and arid parts of the planet had the most ant specimens, while tropical zones had the highest density of ant populations, the researchers found.
"Our results show that the numbers of ants are highest in the tropics, which include areas facing some of the strongest pressures from human disturbances and environmental change," Wong said in the statement.
The scientists called the new estimate conservative and said more research is needed to assess the role that ants play in their terrestrial ecosystems.
"Per hectare, ants move up to 13 tons of soil mass per year," study lead author Patrick Schultheiss, a biologist at the University of Würzburg in Germany, said in a statement. As such, "they have a great influence on maintaining the nutrient cycle and also play a decisive role in the distribution of plant seeds."
Previous studies have had worrying outlooks for the world's insect populations. A series of studies published in January 2021 in the Proceedings of the National Academy of Sciences found that climate change, invasive species, light pollution, changes in agriculture and the use of insecticides and herbicides are collectively causing the loss of around 1% to 2% of Earth's insects each year.
A separate study published in April 2020 in the journal Science found that the planet has lost more than one-quarter of its land-dwelling insects in the past 30 years.
"Ants provide key ecological services — not only in natural systems but also in our farms, plantations, parks and cities — so it is in our best interest to monitor populations and investigate how they are responding to warming climates," Wong said.