If you've ever dealt with an ant invasion in your kitchen and bemoaned the number of ants that seem to exist, a new study can bring some specificity to your complaints. As Science reports, there had been no reliable estimate of the number of ants currently on the planet. An international team of researchers paged through 12,000 reports to identify 489 studies that were sound enough to be included in their meta study. From there, the team arrived at a "conservative" estimate of 20 quadrillion ants on Earth, or 20,000,000,000,000,000, as NBC News translates. That works out to 2.5 million ants for every person. "It's unimaginable," study author Patrick Schultheiss tells the Washington Post. "We simply cannot imagine 20 quadrillion ants in one pile, for example. It just doesn’t work."
And as the researchers from Australia, Hong Kong, and Germany note in the study published Monday in the journal Proceedings of the National Academy of Sciences, that amounts to a pretty massive biomass. Specifically, the planet's ant population "exceeds the combined biomass of wild birds and mammals and equals 20% of human biomass." As study author Mark Wong put it, "We found that there are literally tons of ants on Earth, which really underscores their ecological value." The researchers note that ants aren't distributed equally across regions: They are most plentiful in the tropics, and absent in the polar regions.
The researchers write that their study acts as a crucial "baseline for predicting ants’ responses to worrying environmental changes that currently impact insect biomass." As the Post reports, ants carry out a great many necessary tasks: distributing seeds, aerating soil, decomposing dead wood, and acting as a food source. The team next wants to explore whether the ant population is decreasing, as is the case with many other insect populations. "Ants provide key ecological services ... so it is in our best interest to monitor populations and investigate how they are responding to warming climates," Wong said. (Read more discoveries stories.)