Big Black Ants in the House
Big black ants in the house are almost always carpenter ants, because most other house ants are 1/8 inch or smaller. Carpenter ant workers run about 1/4 to 5/8 inch long. In DFW, they forage at night from a nest in a tree, the yard or damp wood inside. The ants you see are usually scouts from somewhere else.
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Which Big Black Ant Do You Have?
Size settles most cases. This table compares the dark ants that turn up in DFW homes, using measurements from Texas A&M AgriLife's guide to managing household ants and its carpenter ant guide.
| Ant | Worker size | Color | Best clue |
|---|---|---|---|
 Carpenter ant |
1/4 to 5/8 inch | Solid black, or red and black | Workers of mixed sizes, out mostly at night |
| Acrobat ant |
1/8 to 3/8 inch | Brown to black | Heart-shaped abdomen held up over its back |
| Crazy ant |
1/16 to 1/8 inch | Grayish black | Long legs and fast, zigzag running |
| Odorous house ant |
About 1/8 inch | Dark brown to black | A rotten coconut smell if you crush one |
| Little black ant |
About 1/16 inch | Shiny black | Slow, steady trails along baseboards |
Only the carpenter ant is big. If the ant on your counter is longer than a grain of rice, it's almost certainly a carpenter ant. Carpenter ants also have an evenly rounded back with no spines, a single bump at the waist and a ring of tiny hairs at the tip of the abdomen.
The color can fool you. Texas A&M notes that the all-black carpenter ant, the largest species in Texas, lives mainly in wooded areas and rarely causes problems indoors. The kinds that do come inside usually pair a dull reddish front half with a dark rear, and across the room the whole ant just reads as black.
Why Big Black Ants Suddenly Show Up
Carpenter ants live on a night schedule, so a sudden sighting often means the trail was there all along. Texas A&M's carpenter ant guide notes that workers forage mostly at night. They follow fence rails, garden edging, tree branches and water hoses from a nest in a tree to the house.
Weather plays a part too. Texas A&M also links indoor moves to extreme weather, either a long dry heat wave or a soaking wet spell, and DFW summers deliver both. Carpenter ants also swarm from May through July, and winged carpenter ants inside the house usually mean a colony is nesting indoors.
Are Big Black Ants Harmful?
They're more of a nuisance than a danger. Carpenter ants can bite when you handle them, but they don't sting. They don't eat wood either. They hollow out wood that water or termites have already softened, then push the shavings out of the nest.
Texas carpenter ants also do less damage than the species found in other parts of the country. Texas A&M says they rarely damage framing lumber, though home sellers should know that inspectors still count them as a wood-destroying insect. Their presence can point to a leak or rotting wood worth fixing.
How to Get Rid of Big Black Ants
Start by confirming what you have, then find where they live. Each step below comes from Texas A&M's carpenter ant guidance.
- Collect one or two ants on a strip of tape so a technician can confirm the species.
- Check the trail with a flashlight an hour or two after dark to see where the ants enter and leave.
- Look for small piles of wood shavings near door frames, windows and plumbing, which point to a nest nearby.
- Cut back any branch that touches the roof or siding, since it works as a bridge into the attic.
- Skip the grocery-store bait stations, since Texas A&M says they don't work on Texas carpenter ants.
Baits made for carpenter ants can work, but colonies are picky and may refuse a bait one month and take it the next. Our carpenter ant control goes straight into the colony whenever a technician can get to it. If the nest sits inside a wall or a tree, the technician switches to baits and non-repellent sprays that foragers haul back on their own. Homes near our Dallas office can book ant control in Dallas the same way.
Big Black Ants FAQ
Do big black ants mean I have termites?
No, but winged carpenter ants and termite swarmers often show up at the same time in Texas. Check the wings. On an ant, the wings end near the tip of the body or before it. A termite's wings stretch far beyond, sometimes double the body's length.
What kills big black ants for good?
No single spray does it, because the queen stays in the nest. The colony dies when workers carry bait home or when a technician treats the nest itself, which is why finding the nest matters so much.
Why are big black ants in my kitchen at night?
They're foraging. Carpenter ants look for sweets, grease, meat and dead insects after dark, then carry food back to the nest. A kitchen trail at night usually leads back to a tree, a fence or damp wood near the house.
Big black ants that keep turning up after dark point to a carpenter ant nest nearby. Reach us online or by phone for a price, and a technician will follow them home.
