There are about 20 quadrillion ants living on Earth – “a 20 with 15 zeros” — showed findings from a new study.
This figure corresponds to about a fifth of all the mass of every human on Earth, said the research, published in the journal PNAS on Monday.
The study reviewed a range of existing studies on ants, narrowed the research down to about 500 suitable papers and combined their data to arrive at this figure, which is “2-20 times higher than previous estimates”.
“According to our estimates, the global ant population is 20 x 1015 – that is, 20 quadrillion animals. That is a 20 with 15 zeros, which is hard to grasp and appreciate,” study co-author Sabine Nooten said in a statement.
Studies have shown that ants play crucial roles in the ecosystem with the insects moving up to 13 tons of soil mass per hectare every year.
Biologist EO Wilson even famously called the tiny creatures “the little things that run the world”.
The combined biomass of all ants on Earth amounts to 12 megatons of carbon, scientists said, adding that the insects have a great influence on maintaining the nutrient cycle and also play a decisive role in the distribution of plant seeds.
“That exceeds the combined biomass of wild birds and mammals and corresponds to about 20 percent of humanity’s biomass,” said Patrick Schultheiss, another co-author of the study from Julius Maximilians University in Germany.
The tropics have the highest ant density in the world while they do not inhabit the polar regions.
Among ecosystems, forests and arid regions host the most ants, while they are much rarer in parts of the world heavily influenced by humans.
“The density of leaf-litter ants is highest in forests, while the numbers of actively ground-foraging ants are highest in arid regions,” researchers wrote in the study.
Previous estimates of the Earth’s ant population employed a “top down” approach which assumed that ants comprise about 1 per cent of the world’s estimated insect population of 1018 individuals, scientists said.
On the contrary, they said the new research used a “bottom-up” approach to arrive at a “conservative estimate” based on evidence from an “extensive dataset” of globally distributed ant samples.
The new findings highlight the geography of ant diversity and also provide a baseline for monitoring how the insect’s population patterns respond to changes in the environment such as the climate crisis.
