Detection before treatment. Every time. And verification before documentation. Every time. It starts with the dog. It lives with the handler. Every time.
Of all the bats sharing Aiken County with us, the Brazilian free-tailed bat is the one with the best resume. It’s one of the most common attic-dwelling bats in the Southeast, it’s expanding its range into South Carolina right now, and — almost unbelievably — it holds a genuine, peer-reviewed speed record. This post covers its natural history, what it’s actually doing in your attic, and then walks through the part most homeowners never hear correctly: when and why you’re legally not allowed to touch it.
What Exactly Is a Brazilian Free-Tailed Bat?
The Brazilian free-tailed bat (Tadarida brasiliensis) gets its name from its tail, which extends noticeably beyond the edge of its tail membrane — the easiest field mark for identifying it among South Carolina’s bat species, according to the SCDNR Bat ID Guide. It has a wrinkled upper lip, short blackish ears, and dark, velvety fur. It’s also one of the most widely distributed mammals in the Western Hemisphere, found from the southern U.S. through Mexico, Central America, and much of South America.
Natural History & Behavior: Questions & Answers
Q: Is it true this bat set a genuine speed record? A: Yes — a peer-reviewed 2016 study published in Royal Society Open Science (McCracken et al., University of Tennessee, tracked by aircraft over Texas) recorded Brazilian free-tailed bats reaching level flight speeds of up to 100 mph, faster than any bird or bat previously documented in horizontal flight.
Q: So is it faster than a peregrine falcon? A: Not overall — a peregrine falcon’s hunting dive can exceed 200 mph, making it the fastest animal on Earth in any context. But that’s a dive assisted by gravity, not powered flight. In level, flapping flight — no dive, no gravity assist — the peregrine tops out around 60 to 70 mph. The free-tailed bat’s 100 mph is genuine powered horizontal flight, which makes it the fastest animal on Earth at that specific kind of flying, falcons included.
Q: How high do they actually fly? A: Higher than any other bat species. They’ve been documented foraging at altitudes around 10,000 feet, riding wind currents at high altitude to hunt more efficiently, according to wildlife research summarized by Texas Parks and Wildlife.
Q: How big are their colonies? A: Some of the largest mammal gatherings on Earth. Bracken Cave in Texas hosts an estimated 15 to 20 million Brazilian free-tailed bats — the largest bat colony in the world — and the Congress Avenue Bridge colony in Austin (around 1.5 million bats) is famous enough to be a tourist attraction. Colonies in South Carolina structures are nowhere near that scale, but they’re the same highly social species.
Q: What’s the deal with moths evolving to detect bats? A: It’s a genuine evolutionary arms race. Several moth families, including tiger moths and many noctuid moths, have evolved ears specifically tuned to detect bat echolocation calls, letting them take evasive maneuvers or freeze mid-flight. Some tiger moth species have even evolved their own ultrasonic clicks to jam bat sonar. Free-tailed bats are active participants on the other side of that arms race every single night.
Q: What do they actually do for South Carolina agriculture? A: A lot. Bats collectively save South Carolina’s agricultural industry an estimated $115 million a year in avoided pest damage and pesticide use, according to SCDNR. Free-tailed bats specifically target moths whose larvae are major crop pests — including the corn earworm (which attacks South Carolina’s corn crop) and the cotton bollworm (the same species, attacking cotton) — making this one of the more directly agriculturally valuable bats in the state.
Q: Are they actually becoming more common in South Carolina? A: Yes, and fairly recently. Clemson researcher Dr. Susan Loeb, a bat ecologist with the USDA Forest Service Southern Research Station, has noted that free-tailed bats were uncommon around Clemson years ago and now number in the tens of thousands on campus and across the Upstate — a range expansion she attributes to a warming climate, though the exact mechanism isn’t fully understood yet.
Living in Your Home: Why They Pick Attics
Brazilian free-tailed bats are sometimes literally called “house bats” because of how comfortable they are in human structures. Per Texas Parks and Wildlife, they favor roof underhangs, attics, and narrow gaps between signage and buildings — anywhere dark, dry, and undisturbed that mimics the tight rock crevices they’d use in the wild. In South Carolina homes, colonies are typically modest compared to their famous Texas cave roosts — usually somewhere in the range of 30 to 60 individuals in an attic or wall void, according to regional pest industry reporting — but they’re drawn to the same features every time: a warm, dark, enclosed space with a small, defensible entry point. A gap you could fit a couple of fingers into is often all it takes.
Bat Exclusion: When You’re Not Allowed to Touch Them, and Why
This is the part almost nobody hears correctly, and it’s the most important thing to understand before doing anything about a bat colony in a structure.
Bats are protected wildlife in South Carolina. They fall under the state’s nongame wildlife protections, and legitimate removal work follows SCDNR guidance rather than general pest-control judgment call. This was never a spray-and-pray situation, and it was never a “just seal it up” situation either.
There is a legally and biologically enforced blackout window. SCDNR states plainly that there is no humane way to exclude bats roughly from May through July. That window covers maternity season — the period when flightless pups are in the roost, unable to fly, and completely dependent on adult bats coming and going to nurse them.
Why the Blackout Window Exists
- Excluding adults during this window orphans and traps pups. One-way exclusion devices let bats leave but not return. If you install one while flightless pups are inside, the adults get shut out permanently and the pups starve in place — inside your attic, wall, or soffit.
- It creates a worse problem than the one you started with. A colony of trapped, dead pups inside a structure means odor, insect activity, and potential contamination that’s far more difficult and expensive to resolve than the original bat colony ever was.
- It doesn’t even solve the issue long-term. Surviving adults excluded improperly will often attempt to find a way back in, or relocate to another part of the same structure, since the underlying attraction (a warm, safe, enclosed roost) hasn’t been addressed correctly.
- It’s the opposite of what actually works. Correct exclusion timed to the calendar solves the problem once. Exclusion timed to convenience solves nothing and creates new problems.
When Exclusion Can Actually Happen
Per SCDNR guidance, the safe windows are early spring (roughly March–April, before pups are born) and fall (roughly August–October, once pups are flying and self-sufficient). Proper exclusion during those windows follows a specific sequence:
- 1. Inspection first. Confirm species, estimate colony size, and locate every entry point — not just the obvious one.
- 2. Install one-way exclusion devices. These let bats exit to feed at dusk but prevent them from re-entering the same gap.
- 3. Confirm the colony is fully out. This typically takes several days to be certain no bats remain inside, particularly in a structure with multiple entry points.
- 4. Seal every entry point. Once the colony is confirmed clear, every gap gets permanently closed — not just the main one — since bats will readily use any remaining opening.
If you want to actually encourage bats to stick around your property (a genuinely good idea, given what they do for local pest control) without living in your attic, a properly placed bat house well away from the home gives them a legal, low-conflict alternative roost. Check out our blog on nest boxes for guidance on choosing and placing one.
The CK9PS Bottom Line
The Brazilian free-tailed bat is, without exaggeration, one of the more remarkable animals sharing our airspace — a genuine speed record holder that’s also just trying to raise its pups in your soffit. Both things are true at once, and both things should shape how you respond to one. Correct identification and correct timing aren’t red tape for their own sake; they’re the actual difference between solving the problem and creating a much worse one.
Detection before treatment. Every time. And verification before documentation. Every time. It starts with the dog. It lives with the handler. Every time.
Have a suspected bat colony and need it handled correctly — and legally? Contact Coastal K9 & Pest Solutions at 803-226-3155 or ck9ps.com.
Sources
- McCracken, G.F., et al. “Airplane tracking documents the fastest flight speeds recorded for bats.” Royal Society Open Science, 2016 (peer-reviewed)
- South Carolina Department of Natural Resources — “Bats” program page and SC Bat ID Guide; “No humane way to exclude bats from May–July” guidance; SC Bat Conservation Plan
- Texas Parks and Wildlife Department — “Brazilian Free-tailed Bat (Tadarida brasiliensis)” species account
- Bat Conservation International — Bracken Cave colony data
- South Carolina Farm Bureau — interview with Dr. Susan Loeb, USDA Forest Service Southern Research Station at Clemson University
- Jeffcoat Pest and Home Services — regional reporting on structural colony sizes and SC crop-specific pest impacts