Ants are among the most widespread and ecologically important insects on the planet, found on every continent except Antarctica. Their ubiquity prompts a common question: what is the average weight of a single ant? Determining a precise, universal weight is challenging because the term “ant” represents over 13,800 known species with vast differences in size and form. To understand the true weight of the average ant, it is necessary to establish a baseline before examining the variables that make this measurement complex.
Establishing the Baseline Weight
For general scientific estimates, the typical worker ant is most often used to establish an average weight. An individual worker ant generally weighs between 1 and 5 milligrams (mg). This range provides a useful, quick answer, representing many common species found worldwide, such as the widely distributed fire ant, which falls within this bracket.
Smaller species like the Pharaoh ant can weigh as little as 0.5 mg, while common householder species frequently weigh between 1 and 7 mg. This baseline number serves as the figure researchers use when calculating larger population metrics. The majority of the ant population consists of these workers, making their mass the most representative number for a baseline average.
Variables That Change Individual Ant Weight
The 1 to 5 mg baseline is highly variable across the family Formicidae, which contains the world’s ants. Species diversity is the first major factor, with the smallest ants, like those in the genus Strumigenys, being minuscule, while some Australian Bull ants can weigh between 8 and 12 mg. The largest workers, such as the South American Paraponera clavata, or bullet ant, can weigh up to 90 mg, making them many times heavier than the average.
The caste system within a colony also causes significant weight disparities. Worker ants, which are sterile females, are the smallest, but soldiers are often larger with disproportionately bigger heads and stronger mandibles. The queen is exponentially heavier than any worker, with the queen of the African driver ant being known to weigh up to 10 grams, which is thousands of times heavier than her worker offspring.
A third influence on individual weight is the ant’s temporary life stage or load. Foraging ants carrying water or food back to the nest will weigh more than when they leave the nest empty. Certain species, such as honeypot ants, have specialized replete workers that store liquid food in their abdomens, causing their mass to temporarily balloon far beyond their normal body weight.
Calculating the World’s Total Ant Mass
When the tiny mass of an individual ant is multiplied by the estimated global population, the collective weight becomes astonishingly large. Recent comprehensive studies conservatively estimate the total number of ants on Earth to be around 20 quadrillion individuals. This enormous population figure is the starting point for calculating the world’s total ant mass, also known as their biomass.
By multiplying the estimated number of ants by an average body mass, researchers have calculated the total ant biomass. This collective weight amounts to approximately 12 megatons of dry carbon. To provide context for this figure, the total biomass of all ants exceeds the combined total biomass of all wild birds and wild mammals.
The total mass of ants is also estimated to be equivalent to about 20% of the total biomass of all humans on the planet. This calculation relies on the estimated 20 quadrillion individuals, which means that for every person alive today, there are an estimated 2.5 million ants.