In case you ever wondered, there are 20 quadrillion ants in the world. And that makes them important.

Reuters reports on a painstaking headcount that proves that for every one of the nearly 8 billion humans on Earth, there are 2.5 million ants:

“Ants certainly play a very central role in almost every terrestrial ecosystem,” said entomologist Patrick Schultheiss of the University of Würzburg in Germany and the University of Hong Kong, co-lead author of the study published this week in the journal Proceedings of the National Academy of Sciences.

“They are very important for nutrient cycling, decomposition processes, plant seed dispersal and the perturbation of soil. Ants are also an extremely diverse group of insects, with the different species fulfilling a wide range of functions. But most of all, it is their high abundance that makes them key ecological players,” Schultheiss said.

“I was amazed that the ants’ biomass was higher than that of wild mammals and birds combined, and that it reaches 20% of the human biomass. That gives you an understanding of the scale of their impact,” said insect ecologist and study co-lead author Sabine Nooten, also of the University of Würzburg and University of Hong Kong.

The researchers based their analysis on 489 studies of ant populations spanning every continent where ants live.

“Our dataset represents a massive collecting effort of thousands of scientists. We were then able to extrapolate the number of ants for different regions of the world and estimate their total global number and biomass,” Schultheiss said.

Tropical regions were found to harbor many more ants than other regions, with forests and drylands boasting more ants than urban areas.

“There are certain parts of the world where we have little data and we cannot reach reliable estimates for all continents. Africa is one such example. We have long known that it is a very ant-rich continent but also very under-studied,” Schultheiss said.

“Most ants are actually highly beneficial, even to us humans,” Schultheiss added. “Think about the amount of organic matter that 20 quadrillion ants transport, remove, recycle and eat….”

You can read more of Schultheiss and Nooten’s research here, in Proceedings of the National Academy of Sciences.