By following pheromone trails laid by scout ants from their colony, foraging ants can gather and store food efficiently. A scout ant first leaves the nest in search of food, wandering somewhat randomly until it discovers something edible. It then consumes some of the food and returns to the nest in a direct line.

By following pheromone trails laid by scout ants from their colony, foraging ants can gather and store food efficiently. A scout ant first leaves the nest in search of food, wandering somewhat randomly until it discovers something edible. It then consumes some of the food and returns to the nest in a direct line. It seems scout ants can observe and recall visual cues that enable them to navigate quickly back to the nest. Along the return route, the scout ants leave a trail of pheromones—which are special scents they secrete—that guide their nestmates to the food.

Argentine ants, native to South America, now inhabit every continent except Antarctica due to accidental introductions. Each ant colony has a distinctive chemical profile that enables members of the group to recognize one another and alerts the colony to the presence of strangers. Scientists recently discovered that massive supercolonies in Europe, North America, and Japan all share the same chemical profile, meaning they are, in essence, a global supercolony of ants.

Fungus-farming ants began their agricultural ventures about 50 million years before humans thought to raise their own crops. The earliest evidence suggests ants began farming as early as 70 million years ago, in the early Tertiary period. Even more amazing, these ants used sophisticated horticultural techniques to enhance their crop yields, including secreting chemicals with antibiotic properties to inhibit mold growth and devising fertilization protocols using manure.

Ants evolved some 130 million years ago during the early Cretaceous period. Most fossil evidence of insects is found in lumps of ancient amber, or fossilized plant resin. The oldest known ant fossil, a primitive and now extinct ant species named Sphercomyrma freyi, was found in Cliffwood Beach, New Jersey. Though that fossil only dates back 92 million years, another fossil ant that proved nearly as old has a clear lineage to present-day ants, which suggests a much longer evolutionary line than previously assumed.

Quite a few ant species take captives from other ant species, forcing them to do chores for their own colony. Honeypot ants even enslave ants of the same species, taking individuals from foreign colonies to do their bidding. Polyergus queens, also known as Amazon ants, raid the colonies of unsuspecting Formica ants. The Amazon queen finds and kills the Formica queen, then enslaves the Formica workers. The enslaved workers help the usurping queen rear her own brood. When her Polyergus offspring reach adulthood, their sole purpose is to raid other Formica colonies and bring back their pupae, ensuring a steady supply of enslaved workers.

Ants will do just about anything to get the sugary secretions of sap-sucking insects, such as aphids or leafhoppers. To keep the honeydew in close supply, some Ants actually herd aphids, carrying the soft-bodied pests from plant to plant. Leafhoppers sometimes take advantage of this nurturing tendency in ants and leave their young to be raised by the ants. This allows the leafhoppers to raise another brood.

How can this be? After all, ants are so tiny, and we're so much bigger. That being said, scientists estimate there are at least 1.5 million ants on the planet for every human being. Over 12,000 species of ants are known to exist, on every continent except Antarctica. Most live in tropical regions. A single acre of Amazon rainforest may be home to 3.5 million ants.

Ant plants, or myrmecophytes, are plants that have naturally occurring hollows in which ants can take shelter or feed. These cavities may be hollow thorns, stems, or even leaf petioles. The ants live in the hollows, feeding on sugary plant secretions or the excretions of sap-sucking insects. What does a plant get for providing such luxurious accommodations? The ants defend the host plant from herbivorous mammals and insects and may even prune away parasitic plants that attempt to grow on it.