by Frank W. Jennings
"The world’s largest known concentration of mammals"—the bats at Bracken Cave—lies on the outskirts of San Antonio, according to the National Geographic Society.
No wonder that in old books telling about San Antonio’s
by Frank W. Jennings
"The world’s largest known concentration of mammals"—the bats at Bracken Cave—lies on the outskirts of San Antonio, according to the National Geographic Society.
No wonder that in old books telling about San Antonio’s history you can find stories about bats being intimately involved with the city for more than a century.
A visitor to San Antonio in 1846 spoke of the "myriads" of bats that inhabited the abandoned Mission Concepcion.
The local seat of government in the mid-1800s was in a two-story building in Military Plaza called "the Bat Cave," because it housed so many.
During the Civil War, late in 1863, guano, the bat droppings found in bat caves, was used by the Confederacy as a source of saltpeter in a gun powder factory a few miles below San Antonio. The guano was brought in wagon loads from caves 30 to 60 miles distant. Burros, with rawhide boxes strapped on each side, were trained to go into the caves to be loaded with guano.
The world’s first successful experiments with attracting hundreds of thousands of bats to fight malaria-carrying mosquitoes were conducted in the early 1900s by a San Antonio doctor who invented tall towers designed as bat roosts.
Today, bats are still of more than fleeting interest to San Antonians. To avoid colliding with flights of bats, T-38 pilots training at Randolph Air Force Base take special precautions from April Fools’ Day until Halloween. They suspend their daytime flying at 30 minutes before official sunset, and don’t take off again until 30 minutes after sunrise.
If you were to drive northeast on Interstate 35 toward Austin—just outside Beltway 1604 on the edge of San Antonio—you might see Bat Cave Road heading north to old Nacogdoches Road and Bracken Cave.
Within 80 miles of San Antonio are three very large bat caves -- plus possibly the largest urban bat colony in the world. Some 750,000 bats live under the Congress Avenue Bridge in downtown Austin.
The largest colony of Mexican free-tail bats on Earth is in Bracken Cave, privately owned in Comal County. There are more than 20 million bats there—the largest known grouping of warm-blooded animals anywhere. The Frio Cave in Uvalde County and the Ney in Medina County are also among the world’s large bat caves.
As nightfall approaches—as long as two hours before sundown—what appear to be dark clouds of bats come swirling and billowing out of Bracken Cave, making a clockwise circle and flying off to the south.
Even from two miles away, great columns of the bats can be seen rising from the cave. They may ascend to altitudes above 10,000 feet, where tail winds can help them achieve speeds of more than 60 miles per hour en route to distant feeding grounds.
In one hour one bat can eat 100 or more night-flying insects. The bats at Bracken Cave consume an estimated half a million pounds of insects nightly.
According to Merlin D. Tuttle’s popular book, America’s Neighborhood Bats, "given the incredible numbers of insects eaten, including many pest species, free-tailed bats undoubtedly play a vital role in the checks and balances of nature."
Tuttle, who is founder and science director of Bat Conservation International, an educational and protective organization with headquarters in Austin, spends a great deal of time spreading the word that bats are not flying rodents, they’re very special animals. They’re closer to the monkey and ape family than to any other, but they’re different.
Bat Conservation International dispels old myths about these mysterious and sadly misunderstood night creatures, proving that they’re our friends, not our enemies.
Bats can see quite well and also have a kind of sonar. They have no interest in getting into people’s hair, as some folk believe; further bats are no more rabid than any other wild mammal. More people die from dog bites in one year than from bats in decades. Only 10 people in the U.S. and Canada are believed to have died from bat rabies in the past forty years. Yet, hundreds of thousands of bats live in buildings in cities where they’re close to people.
There are nearly a thousand kinds of bats: some, the world’s smallest mammals, the size of bumblebees, weigh less than a penny; some bats, called "flying foxes," have six-foot wingspreads. Some eat fruit; some, much like bees, eat nectar. Many important plants and trees owe their survival to the pollinating habits of bats.
Without bats we’d be without many fruits, nuts and spices, or even tequila and rope fiber, which come from the agave plant. We can thank bats for our bananas, dates, figs, avocados, mangoes and cloves.
They’re our planet’s most important predators of night-flying
insects, they provide tons of valuable fertilizer, guano, in countries
where it’s collected, and