A fun fact to share over drinks: just northeast of San Antonio, as many as 20 million Mexican Free-tailed Bats roost in a cave from March to October, making their summer home right here in our area. That also makes the cave the largest known concentration of mammals on earth. What?—you mean you didn’t know? Well, don’t worry—you’re not alone. I’d missed this interesting tidbit and had no idea that San Antonio was so popular with winged nocturnal tourists.
I’m not a bat aficionado, but these little nighttime friends offer quite a show. Each March, some 10 million female Mexican Free-tailed Bats migrate from Latin America to roost in Bracken Cave, where they give birth to five to six million (or more) juvenile bats each June. These bats use the surrounding countryside to learn to fly and forage for insects. Every night for three or four hours from March through October, these millions of bats spiral counter-clockwise out of the cave each night, on their way to hunt a tasty insect dinner at speeds of up to 60 miles per hour.
Bracken Cave is situated on the Bracken Cave Preserve, almost 700 acres of land owned by Bat Conservation International (BCI). At the height of summer, the Bracken bat colony eats 140 tons of insects each night as these summer residents forage the surrounding countryside and beyond. In fact, they actually travel up to 60 miles away each night, meaning that they complete a 120-mile round-trip to forage, eat, and explore before returning home to the cave at sunrise.
The preserve is located in southern Comal County, just outside of San Antonio in Bracken, near Natural Bridge Caverns. While we live just minutes from the cave, I had no idea it was there until news broke that the area around the cave was about to be turned into housing development. While BCI owns the 700 acres surrounding the cave, a developer had plans to build upon land adjacent to the preserve.
In addition to its close proximity to the globally renowned bat cave, the land marked for development lies entirely within the Edwards Aquifer Recharge Zone. As one of the most prolific artesian aquifers in the world, the Edwards Aquifer provides drinking water for roughly two million central Texans, including the entire city of San Antonio.
Needless to say, this isn’t an area that needs to become a housing development. And thanks to a unique partnership between the City of San Antonio, The Nature Conservancy, and BCI, the land was purchased for $20.5 million in 2014. BCI and The Nature Conservancy own the land in fee title, and the City of San Antonio holds a conservation easement on the property. Three cheers for our little summer tourists and bug foragers, not to mention all of us who depend on the Edwards Aquifer for our water.
Now, cue the Batman theme song and let’s get back to our story: the unforgettable scene of millions of bats swirling out of the cave and how we non-nocturnals can see this stunning show. Access to the cave is restricted to protect the habitat of the resident bats, but BCI offers evening guided tours to allow the public to watch the bats emerge from the cave. Additionally, BCI hosts special nights for BCI members, providing them an opportunity to make reservations for a viewing. Founded in 1982 and based in Austin, BCI is devoted to conservation, education and research initiatives involving bats and the ecosystems they serve.
Another option is Bracken Bat Flight, a combined cave- and bat-viewing package offered through a partnership between Natural Bridge Caverns and BCI. The package includes a tour of Natural Bridge Caverns, followed by a bat viewing. The package has been available for summer 2015 with dates into August. Check with Natural Bridge Caverns for more details.
What does a viewing entail? Joining BCI staff and volunteers for a pre-sunset talk about the bats and then front-row seats for a show that must be seen to be believed. As a maternal colony, the Bracken bats feature moms and their babies. (The “daddy bats,” as my Little called them, and nonreproductive females live separately in bachelor colonies, one of which can be found in downtown San Antonio on the Museum Reach at the Camden Street Bridge. The San Antonio River Authority and BCI host “Bat Loco” events on the Museum Reach that focus on the colony, but this year’s bats are coming out much later than previous years: the spring rains mean more insects/less work foraging, so the Camden Bridge colony may be harder to spot this summer.)
As for the Bracken moms and their babies, neither words nor still photos do them justice. After driving into the preserve—which is gated and only open during hosted events and requires visitors to pre-register to enter—you drive 1.7 miles to the parking area. From there, viewing requires walking a half-mile into the area of the cave. You’re in what looks like an amphitheater, but instead of a stage, there’s a 100-foot-wide hole, and while the sun is still in the sky, you can see bats fluttering about the opening.
The cave itself is about two football fields long and 80 feet deep, but only researchers venture in and never when the bats are in residence. Honestly, the description of the cave’s insides is not pretty: mites, scorpions, fleas, and bat poop, otherwise known as guano, which is believed to be 19 meters deep or more—the researches would like to do core samples for carbon dating. I appreciate the science behind that, but YUCK. The smell outside of the cave—an occasional whiff of guano on the wind—was more than enough to tell me I don’t need to be any closer.
As the sun begins to set, you stare down into the crescent-shaped opening as you sit on benches and natural rock formations, waiting for the fun to begin. The sun slips lower in the sky, and as it starts to dip below the trees on the horizon, a ribbon begins to spin out of the cave. Few in number at first, then more and more movement as the bats start on their nightly journey. Like you, your fellow viewers are sitting in awed silence as you watch the bats emerge. By the way, bats don’t like noise, so you need to be quiet so as not to interrupt their journey, which isn’t hard because, honestly, words escape you as they continue to spill out of the cave. The ribbon of bats is “like a current,” in the words of Little, our four-and-a-half-year-old, who couldn’t quite grasp what all was happening but decided he really likes bats.
The sky above the viewing area fills with bats, and if you cup your hand behind your ears, you can hear their wings as they fly. You can also hear them “talking” to each other: little bat sounds that make you wonder if they’re discussing where they’ll go for the night and what sort of bugs are on their breakfast/lunch/dinner menu.
After the bats begin to emerge, BCI volunteers and staff escort you to the back side of the cave—a straight shot from the viewing area, accessible down a gravel path. While you can’t see the mouth of the cave from that angle, the site of the bats filling the sky, with the remains of the setting sun as their backdrop, leaves you with your mouth open as you ponder nature’s beauty and the wonders of these little creatures.
A few misconceptions about our misunderstood nocturnal winged friends: they are not blind or dirty, nor are they looking to nest in your hair. They have excellent vision and, of course, use biological sonar to hunt in total darkness and groom their fur like cats do. And despite what Hollywood would have you believe, they don’t suck blood—at least, not mos of them. Only three of more than 1,300 bat species are vampire bats that feed on blood. All of these reside in Latin America, only one of the three vampire species targets mammals, and that one prefers domestic livestock, so really, you’re safe.
Bats are also not rodents; they’re mammals—and yes, they nurse their young. Some nurse for as long as six months and will carry their babies with them when they fly. Imagine what it’s like to breastfeed while hanging upside down or in flight—c’mon, you know that can’t be easy! Give these little mamas some respect! And while she lives in a colony with millions of other bats, a mama bat can return and find her little one by voice and smell. Once again, bravo, mama bats!
So cool factor aside, why should you appreciate bats? Because they help pollinate a number of plants (including avocados and agave—hello, can you say guacamole and tequila?!), and their voracious little tummies really like insects. A mother bat can eat up to her body weight in insects every night, and a million bats can eat as much as 10 tons of bugs. That appetite helps save American farmers more than $3.7 billion each year and cuts down on pesticide use.
And while we’re talking bat facts, let’s talk safety. Though the incidence of rabies in healthy bat populations is as low as—or lower than—1%, 10 to 25% of all sick or dead bats found on the ground in Texas test positive for rabies. Anyone handling a bat without wearing gloves may be required to receive preventative rabies shots, so keep in mind and share with your children that a bat found on the ground is not to be touched. You can contact animal control for safe disposal.
A few things to know about the tours—and BCI’s FAQ section is something you should check out if you’re interested in attending a viewing. It will give you tips on what to bring (bug spray is a must, as are closed-toed shoes; binoculars can help you watch as hawks and falcons see if they can snag a bat for dinner; and leave your pets and smokes at home).
First thing to know: this is an adventure that requires planning. You must pre-register, and spots fill quickly, so if this is something you want to do, plan in advance by visiting the BCI webpage to check out public and member nights. (Hint: you want to become a member.)
(By the way, members can participate in overnight camping events and morning return viewings that allow you to see the bats come home. While I’m more of a glamping gal, as I watched the sun coming up the morning after our viewing, I couldn’t help but wonder if the bats were all making their way back to the cave. And the thought of that show does sound fun: mama bats, flapping along with bellies full of bugs, and babies, full of insects and new adventures, gliding their way down into the cave to roost and rest for the day, wondering if they should tell mama about their latest outing.)
Second: make sure your children are old enough for a viewing. While we took our four-and-a-half-year-old, BCI recommends viewing for ages six and up. After attending a viewing, this mom agrees. As cool as this is, it’s hard for children to sit still and stay quiet. For their safety, they can’t roam and play—this is undeveloped land, and while BCI has cleared a great area for viewing, you don’t want your children exploring on their own. The night of our visit, even children ages eight to ten were losing interest, and you can’t just leave at any time—everyone enters and leaves the area as a group, so you’re there for the full evening (meaning you depart around 9:30 P.M.). So know your child’s limits, and perhaps make this an incredible date night: just you and your special someone watching the sunset with millions of bats. What could be more romantic?!
Third, consider supporting BCI. With support, BCI can help protect bats and preserve areas like the Bracken Cave, making sure your kids can witness this wonder and perhaps share it with their own children someday. We’re adopting a bat for our Little so he’ll continue to learn about bats. (Note: no live bats will be sent your way, I promise!) You can even adopt and join BCI at the same time through a special offer detailed on the bat adoption page.
The night of our viewing, a professional photographer was capturing shots for an Edwards Aquifer Authority calendar. As he said, the only way to really get the proper images would be to add professional lighting, etc., which of course would destroy the environment and thus the shot. It really is something you have to see. But you have to see it responsibly: follow BCI’s guidelines and register for a viewing, respect the preserve and its precious environment, and enjoy a spectacular show.