Ants are our co-rulers of the land. An estimated ten thousand trillion strong worldwide, they weigh very roughly the same as all of humanity. They abound everywhere except on icy mountain peaks and around the Poles. From underground to treetops, they serve as the chief predators of insects and other invertebrates and the principal scavengers of small dead bodies. Although their 12,000 known species compose only about 1.4 percent of the world's insect species, their share of the collective body weight is easily ten times greater.
I was ﬁrst drawn to these remarkable creatures almost 70 years ago as a boy in Washington, D.C. Inspired by the tales of Frank Buck and other wildlife adventurers,I launched my own expeditions from our family apartment into the "jungles" of Rock Creek Park. Ants especially intrigued me because of an article by William M. Mann in the August 1934 National Geographic: "Stalking Ants, Savage and Civilized." Mann was also director of the National Zoo, hence doubly my hero. The myrmecological lineage continued decades later with Mark Moffett, who earned a Ph.D. under my direction at Harvard and whose groundbreaking photography of ants focuses in this issue on army ants.
Ants are important for more than their ubiquity and environmental impact. They also exhibit social behavior as exotic as any we may ever hope to ﬁnd on another planet. For most of each year colonies consist only of females: queens that reproduce for the colony and infertile workers that conduct all the labor. Males are bred and kept for short periods, exclusively for the insemination of virgin queens. The communication systems of ants are radically nonhuman. Where we use sound and sight, they depend primarily on pheromones, chemicals secreted by individuals and smelled or tasted by nestmates. Since the brain of an ant weighs less than one-millionth as much as a human brain, it is not surprising that a given species produces just ten to twenty signals. Unlike human language, these messages are entirely instinctual.
These marvelous little creatures have been on Earth for more than 140 million years. The most complex social organizations among them, such as those of the army ants and leafcutter ants, rank with Earth's greatest wildlife spectacles. Ants easily outlasted the dinosaurs, and they will easily outlast humanity should we stumble.