We know them. We love them. And much of the world misunderstands them.
Flying hunters that come out at night, these mammals have gotten a bad rap over the years (think Dracula). South Texans, however, know their importance. They call the region home between April and October.
That said, here are some things you may not know about our nocturnal buddies.
Yes, bats are mammals, which means they give birth. That usually happens in maternity roosts like Bracken Bat Cave, which sits just outside of San Antonio. It’s home to the largest Mexican free-tailed bat colony in the world, with an estimated 15 to 20 million bats.
Yes, they only come out at night
Bats are nocturnal, so yes, they generally only come out at night.
“They’re kind of like teenagers. They’re up all night, sleep during the day and smell bad,” said Fran Hutchins, local bat guru and longtime director of the Bracken Bat Cave Reserve.
So when it’s dark, that’s when the party starts — and all they do is eat.
They eat tons of bugs...literally
“They are the biggest nighttime bug eater that we have here in Texas. So, for example, at Bracken Cave, that colony of bats is eating over 150 tons of bugs at night. That’s like 280,000 Whataburgers in food each night,” Hutchins said.
That’s a lot of burgers, or bugs, rather. And this feast is super helpful to the farmers in the area.
“For all the insects that they are eating, that prevents crop damage,” Hutchins said. “We don’t have to spray pesticides on our crops, all those kinds of things, so they’re just a significant benefit to our local farmers.”
The Mexican free-tailed bat can travel 60 miles round-trip foraging for food each night. They fly as high as 10,000 feet in altitude.
Bats have not always been valued
Did you know that thousands of Mexican Free-tailed bats were going to be used as expendable weapons in World War II? An exhibit at the Kendall County Historic Jail Museum in Boerne explains the whole thing.
Long story short, the United States military spent $2 million on a project that called for placing thousands of bats, with attached incendiary devices, inside a bomb. That bomb was to be dropped on Japan, with the hopes of catching buildings on fire.
How close did it come to actually happening?
“I think they were pretty serious, and they had a lot of people working on it,” said Paul Barwick, who runs the museum.
Now, we cherish them.
San Antonio even has a brewery named in their honor. Freetail Brewing Company boasts a bat silhouette on their beer.
In San Antonio and Austin, crowds gather during the evenings to see the mass exodus of the bats, and thousands come from around the world to see the “great emergence” from the Bracken Cave.
There are male-only colonies
One such example is under the bridge of Interstate 35 as it crosses Camden Street in San Antonio. A bachelor colony calls this roost home.
“So the males, you know, go to these bachelor colonies and they’ll just be the males hanging out,” Hutchins said.
However, mother bats do a lot of work, too.
“So, the mothers are going to be nursing the babies here around mid-June when they start having them,” Hutchins said.
It’s estimated that baby Mexican free-tailed bats roost in densities of up to 500 per square foot. Incredibly, mother bats are able to find their own babies amongst thousands of pups by using their sense of smell and hearing.
You can see bats on local radar
In some cases, like with Bracken Cave, the colonies are so big that they can be seen on radar in the evening when leaving to hunt for food.
That is also the case in the mornings when they fly back into their caves. You might even see KSAT meteorologists point it out on Authority Radar from time to time.
Researchers are concerned about low bat numbers
Recently, KSAT was given the rare opportunity to rappel down into the Devil’s Sinkhole, another important South Texas bat roosting spot. Hutchins was there to conduct important research, as the population of bats has inexplicably dropped.
“They just may have moved to where there’s a better food source, but we just don’t know. So, but it’s something we’re investigating,” Hutchins said.
The drought may also be playing a role. Either way, they hope it’s not disease.
Disease is a real threat to bat survival
While down in the Devil’s Sinkhole, researchers swabbed for disease.
“We also will swab the substrate looking to see if there’s any evidence of Pseudogymnoascus destructans fungus, which is what causes white nose syndrome,” Hutchins said.
Thankfully, none was found inside the cave, but it has been detected in parts of Texas. It is a real threat to the state’s bat population.
“This cold-loving fungus is affecting our hibernating bats. So when these bats go into these caves to sleep through the winter, when it’s really freezing cold outside, the fungus grows on them as an irritant,” Hutchins said. “It kind of messes up their hibernation cycle when they wake up. They use more energy to do that. They burn off their fat reserves, and they end up starving to death.“
The Mexican free-tailed bat can even reach speeds of 100 miles per hour.
“You know, bats have such a horrible reputation. You know, of course, they can scare you in the night, but they’re the sweetest, kindest little creatures. And the Mexican free-tailed is just astonishing. You know, it weighs what three nickels weigh. It flies 100 miles an hour,” said Andrew Barnebey, a longtime guide at the Devil’s Sinkhole State Natural Area.
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