A termite colony isn’t a single visible structure in most cases. What it looks like depends entirely on the species. Subterranean termites build networks of mud tubes and underground galleries you’d never see unless you went looking. Drywood termites live entirely inside the wood they eat, leaving almost no external trace. And mound-building species (found in tropical regions, not North America) construct towering earthen structures that can reach over 15 feet tall. Here’s what each type looks like, from the outside in.
Subterranean Colonies: Mud Tubes and Underground Networks
Subterranean termites, the most common and destructive type in the United States, build their main colony underground in the soil. The colony itself is a sprawling network of tunnels and galleries carved through dirt, connected to above-ground food sources by mud tubes made from soil, wood particles, and termite saliva. These tubes are the most visible sign of the colony’s existence. They’re earth-colored, roughly the width of a pencil, and typically range from 1/4 inch to 1 inch in diameter.
There are several distinct types of mud tubes, each with a different look. Exploratory tubes are thin, fragile, and branch out in multiple directions as workers search for new food. They can extend up to 15 feet above ground when built over concrete or metal surfaces. Working tubes (also called utility tubes) are sturdier and built to last, running along basement walls and foundations as permanent highways between the nest and food. Drop tubes hang suspended between the ground and wooden structures, looking like tiny stalagmites in a cave. They’re lighter in color than other tubes because they contain more wood fiber.
Before a swarm, workers also build temporary structures called swarm castles, wide platforms that can reach four feet across and serve as launch pads for the winged termites leaving to start new colonies.
Drywood Colonies: Hidden Inside the Wood
Drywood termite colonies look completely different because they live entirely inside the wood they consume. There are no mud tubes, no underground tunnels, and no visible nest. The colony exists as a series of feeding galleries carved through lumber, furniture, or structural wood. Large galleries connect to smaller ones through a maze-like network, and the interior surfaces are remarkably smooth, almost as if sanded down.
Drywood termites eat both with and against the wood grain, which is unusual. They often consume nearly all the wood inside a board, leaving just a paper-thin outer shell. A piece of infested lumber can look perfectly fine from the outside while being almost completely hollow. The only external clues are tiny “kick-out” holes where termites push out their waste pellets (called frass), though they often plug these holes with cemented frass. Below those holes, you’ll find small piles that look like fine sand. Under magnification, each pellet is about one millimeter long with six concave sides, distinguishing it from actual sand grains.
Tropical Mounds: Towers of Soil and Engineering
The most dramatic termite colonies belong to mound-building species found in Africa, Australia, and South America. These mounds are constructed from a mixture of soil, termite saliva, and dung. They appear solid from the outside, but the walls are filled with microscopic holes that make the entire structure porous and breathable.
Inside, the architecture is surprisingly complex. The top section features a central chimney surrounded by an intricate network of tunnels and passages that function as a ventilation system. Fresh air enters through the porous walls, travels through small tunnels to the central chimney, rises as it warms, then cools and sinks back down. This cycle constantly circulates oxygen through the mound and keeps the internal temperature nearly constant.
Termites don’t actually live throughout the mound. The nest itself sits at or below ground level, made up of numerous galleries separated by thin walls. Inside the nest are fungal gardens, carefully maintained chambers where termites cultivate a specific fungus that helps them digest wood. The temperature control provided by the mound’s architecture is precise enough to keep these gardens thriving. Six feet below ground level sits the cellar, the coolest part of the structure, with a ceiling of thin plates that absorb moisture from the colony above. As that moisture evaporates, it cools the surrounding air. At the mound’s base, several openings serve as entry and exit points for foraging workers.
What the Termites Themselves Look Like
A termite colony contains several visually distinct castes, and most people are surprised by how different they look from one another.
Workers make up the bulk of the colony. They’re completely white, eyeless, and soft-bodied, roughly the size of a grain of rice. Unlike ant colonies where all workers are female, termite workers can be genetically male or female, though they function identically. These are the termites doing all the tunneling, feeding, and caretaking.
Soldiers are the next most common caste and easy to spot. They have noticeably enlarged, darker-colored heads and heavy, elongated mandibles (jaws) that they use to defend the colony. Their bodies are still pale, but the contrast between the dark head and light body makes them unmistakable.
Swarmers (also called alates) are the only termites you’re likely to see out in the open. They’re the only caste with eyes and pigmentation, since they’re the only ones that leave the colony and encounter sunlight. They have two pairs of equal-length wings, which they shed after landing and pairing up to start a new colony. Piles of discarded wings near windowsills or light fixtures are one of the most common first signs of a termite problem.
The queen is the most dramatic-looking member of the colony. In mature colonies of mound-building species, a queen’s abdomen swells enormously as her egg-producing capacity ramps up. Some queens lay around 40,000 eggs per day and can continue at that rate for decades. She and the king reside in a dedicated royal chamber within the nest, tended constantly by workers.
Signs of a Colony in Your Home
Most people searching for what a termite colony looks like are really asking: what would I see if termites were in my house? The colony itself will almost certainly be hidden, either underground or inside your walls. What you’ll notice are the clues it leaves behind.
For subterranean termites, the most telling sign is mud shelter tubes running up your foundation, either on exterior walls or inside a crawl space. You might also spot BB-sized dots of dried mud on interior walls or ceilings, sunken winding lines in wallpaper or paint, or odd formations of dried mud sprouting from walls in late spring (those are swarm castles). Structural symptoms like sagging floors, a soft door frame, or a bouncy section of subflooring can indicate long-term damage.
For drywood termites, look for accumulations of tiny, uniform, six-sided pellets on floors, countertops, or windowsills. These frass piles often appear directly below a small hole in wood or drywall. You may also discover hollowed-out wood during remodeling or repairs, with smooth internal galleries and a tissue-thin exterior shell that crumbles under light pressure.
In either case, seeing winged termites emerging from walls, ceilings, or floors, or finding piles of shed wings indoors, is a strong indicator that a colony is living inside or directly adjacent to the structure.