Ants have been called one of the most successful organisms on Earth. Their numbers boggle the mind. In terms of biomass (the amount of living matter), ants make up at least 15 percent of the terrestrial animal biomass. In tropical areas, such as the Amazon, this number increases to 25 percent or more of the terrestrial animal biomass. One hectare (about 2.5 acres) of land in the Amazon rain forest can contain eight million ants or more. A study in the savanna of Côte d'Ivoire showed that a hectare there harbored 20 million.
Ants are successful not only in terms of sheer numbers, but in their geographical coverage of Earth, as well. There are only a handful of spots where native species of ants do not exist—Antarctica, Greenland, Iceland, parts of Polynesia, and a few other extremely remote islands in the Atlantic and Indian oceans.
—Alice S. Jones