Ants live on every continent except Antarctica, and they nest in an enormous range of places: underground in soil, inside dead or living trees, beneath rocks, inside walls of houses, and even in hollow acorns. More than 13,800 species have been described so far, with estimates suggesting around 22,000 exist in total. Where any particular ant lives depends on its species, but the basic nest design is always a variation on the same ancient blueprint: a vertical shaft leading to one or more horizontal chambers.
Underground Nests
Soil is the most common nesting habitat for ants worldwide. A typical underground nest starts as a simple vertical tunnel with a few small chambers branching off it, and the colony expands from there. Some species build remarkably deep structures. Excavations of Florida harvester ant nests, for example, have revealed colonies deeper than a person is tall, requiring researchers to remove two to four tons of sand to expose the full architecture. A colony of about 7,000 workers, weighing less than an ounce combined, moves more than 16 pounds of soil to create a nest with a volume over two gallons.
The internal layout is more organized than it looks from the surface. Chambers are perfectly horizontal, connected by sweeping helical shafts, and they get simpler the deeper they go. Ants sort themselves by age and job: the youngest workers stay in the deepest chambers caring for the brood and queen, middle-aged workers handle general nest maintenance in the center, and the oldest workers occupy the top chambers, where they leave to forage. This whole structure isn’t permanent. Many colonies relocate about once a year, building a new nest and moving into it in four to six days. The cumulative distance traveled by sand-carrying ants during a single excavation can exceed 400 miles.
Trees, Logs, and Dead Wood
Living tree canopies and dead wood are the other two major ant habitats. Standing trees, stumps, fallen logs, and even small items like seedpods and acorns all get colonized when they have existing cavities or softened wood that ants can excavate. Many species in the genus Camponotus (carpenter ants) nest in both live trees and dead wood across temperate, subtropical, and tropical forests. Other common species, like those in the genera Aphaenogaster and Pheidole, build nests in rotten wood that extends down into the surrounding soil, blurring the line between wood and underground nesting.
Some arboreal species take a different approach entirely. Weaver ants construct nests from living leaves, binding them together using silk produced by their larvae. Others build “carton” nests from chewed plant material mixed with saliva, creating papery structures attached to branches. These above-ground nests are especially common in tropical forests, where ant diversity is highest and canopy real estate is valuable.
How Carpenter Ants Use Wood
Carpenter ants are worth understanding on their own because they’re one of the most common household pests, and people often confuse them with termites. The key difference: carpenter ants do not eat wood. They chew through it with their jaws to create tunnels and galleries for nesting, leaving behind smooth, sandpapered-looking channels and piles of fine sawdust. Termites actually consume the wood as food.
Outdoors, carpenter ants prefer tree holes, stumps, logs, and standing dead trees. They’re drawn to wood that’s already moist or decaying because it’s easier to excavate. Carpenter ants also maintain satellite nests in addition to their primary colony. Workers will leave the main nest, take some larvae and pupae with them, and establish a secondary location. This means a single colony can occupy multiple sites simultaneously, which is one reason they’re so persistent once they move into a structure.
Where Ants Nest Inside Homes
When ants move indoors, they almost always follow moisture. The most common indoor nesting sites are wall voids, spaces behind cabinets and appliances, gaps behind door and window frames, areas under floors, and voids beneath concrete slabs. Different species have different preferences:
- Carpenter ants target moist or rotting wood, including areas behind bathroom tiles, around tubs and dishwashers, under roofing, in attic beams, and even inside hollow doors and curtain rods. They’ll also tunnel into soft polystyrene insulation.
- Odorous house ants nest in wall voids and under floors, especially near moisture sources like kitchens and bathrooms.
- Pavement ants nest under concrete slab foundations and enter through cracks. They also turn up in wall voids.
- Pharaoh ants nest strictly indoors in northern climates and cannot survive outside. They occupy tiny cracks and crevices, including spaces behind countertops, baseboards, and inside wall voids, favoring dark, warm spots near water.
- Acrobat ants nest in wall voids and rotted wood, with a particular affinity for damaged window frames.
- Thief ants squeeze into very small spaces: under countertops, inside cabinet voids, behind baseboards.
Pharaoh ants have an especially frustrating survival strategy called budding. When a colony gets too large or feels threatened (including from pesticide exposure), a group of workers grabs some larvae and pupae and relocates to a new site, often with a queen in tow. This can cause a single colony to split into multiple nests throughout a building.
Signs of a Nest in Your Home
Seeing a trail of foraging ants doesn’t necessarily mean there’s a nest inside your house. Many species forage indoors but nest outdoors. The strongest indicator of an actual indoor nest is finding winged ants swarming inside the building. These are reproductive ants leaving the colony to mate, and their presence indoors, especially during winter, points to a nest inside the structure. Pavement ants and larger yellow ants commonly swarm indoors during winter when they’re nesting under heated concrete slabs.
For carpenter ants specifically, look for small piles of fine wood shavings near baseboards, window frames, or wooden beams. The tunnels they leave behind are clean and smooth, distinctly different from the rough, mud-packed galleries termites create. Larger yellow ants sometimes give away their location by pushing dirt or cement particles out of cracks in foundations, though they don’t actually damage the masonry or wood.
Global Distribution
Ants are found almost everywhere on Earth except Antarctica, Iceland, Greenland, and a handful of remote island nations. Their diversity peaks in the tropics, but they occupy deserts, grasslands, temperate forests, and urban environments across every other continent. Conservative estimates put the global ant population at roughly 20 quadrillion individuals. Their combined dry biomass exceeds that of all wild birds and mammals on the planet.
This extraordinary success comes down to flexibility in nesting. The ancestral ant nest was nothing more than a vertical shaft and a few horizontal chambers. Every modern species builds some variation of that original design, whether it’s a sprawling underground city, a leaf-bound canopy nest, a colony inside a single acorn, or a network of tunnels behind your kitchen wall. That adaptability is what lets ants thrive in nearly every habitat the planet offers.