Inner Space Cavern, located in Georgetown, Texas, has become a bat education center thanks to cooperative tricolored bats (Perimyotis subflavus) and tour guides who love them. More than 300,000 visitors a year will have a close-up encounter with bats during their guided tour.
Tricolored bats can be seen year-round, often roosting within a few feet of passing visitors. Assistant Manager, Patty Perlaky, commented, “I think one of the most exciting things for people, especially the children, is to see a live bat in real life, not on TV.”
The cave itself has a long and fascinating history. Approximately 13,000 to 32,000 years ago it had up to five entrances, some quite large. Ancient bones and carbon dating reveal the cave was visited by saber-toothed cats, jaguars, ground sloths, spectacled bears, dire wolves, camels, and even an occasional mammoth.
Calvin Butchkoski wasn’t privileged to attend graduate school. In fact, he never even took a course in bat biology while earning an associate degree in wildlife technology at Penn State. Yet, he became his state’s all-time leader in bat conservation. His amazing career is a testament to the power of following one’s passion while caring for both bats and humans.
Unable to find employment as a biologist, he served in the Marine Corps for three years after college. Finally, in 1982, he was hired as a biology technician by the Pennsylvania Game Commission where he assisted in studies of wild turkeys, bears, and even packrats for two years. He didn’t discover his true passion until assigned to work with bat expert, Dr. John Hall.
Despite a late start and lack of formal training, mostly self-taught, Cal quickly became one of America’s foremost bat conservationists. In fact, he led Pennsylvania to become a national model. His achievements include key bat house discoveries, the establishment of America’s first citizen science bat counts, protection for the state’s most important hibernation sites in caves and mines, special training for hundreds of state and federal employees, and highly successful public education campaigns.
Cal led early research on the most appropriate bat house designs for Pennsylvania and helped homeowners solve nuisance problems caused by too many bats attempting to live in walls and attics. His bat house alternatives saved thousands of bats from extermination. And homeowners often became citizen scientists volunteering their help with annual emergence counts.
Given overall warming trends, we weren’t surprised to see some 70 to 80° F days in January and February of 2021. But that hardly tells the full story!
Beginning on February 10th, historically low temperatures were recorded across Texas. For eight consecutive days (February 10–18), the temperature hovered between 37° and 9° F with six inches of snow on the ground in Austin, Texas. The first reasonable feeding opportunity for bats likely didn’t occur before the 21st.
The last similar event occurred 32 years ago in 1989. In a 9-day period (December 16–24) the daily temperature ranged from 51 to 4° F but remained below freezing for only two days versus seven in 2021. Fewer people were concerned in those days, but at least hundreds of killed bats were reported.
For many years we’ve wondered just how many Brazilian free-tailed bats (Tadarida brasiliensis) could cram into a single 18-inch-deep bridge crevice. Accurate counts of large colonies are difficult no matter how they’re made. However, when estimating bridge colonies, it would help if we knew the number, using an average horizontal foot of crevice.
The solution seemed easy. Two years ago, Glen Novinger, an MTBC member and I, inserted two, three-quarter-inch-thick wooden frames, each encompassing a square foot of interior space, into bridge crevices of the same width while the bats were out feeding. The idea was to later slowly remove them, forcing those roosting inside to exit into a cloth-lined bag from which we would count them.
However, the bats were full of surprises. The first night we waited patiently till half an hour after we’d seen the last ones leave—or at least that was what we thought! But when we approached to install our devices, roughly half remained inside. I couldn’t help but wonder how many emergence counts had missed those that, for whatever their reasons, didn’t emerge at sundown. (more…)
Every year around this time there is a spike in needlessly sensational rabies stories featuring exaggerations of truth. We always encourage others to respond politely to editors, authors, decision makers and media personnel when they see these. Editors’ jobs depend on readership and they do aim to please. They just need to know you like or dislike an article. Responses can be very simple such as, “I don’t appreciate sensational headlines or speculation that creates needless fear of bats.”
We work hard to be a source for your personal ambassadorship of bats and wish we could respond to every article, however our resources are limited. We cannot do it alone. We hope that this post will supplement your future responses when you encounter false or exaggerated bat publicity.
Unfortunately, this well intended story is a sensational exaggeration of truth. It is correct to say that most human rabies in America comes from bats. However, put in context, it’s just 1-2 cases per year, making it one of the rarest causes of death. By comparison, just by riding one mile in a motorized vehicle, an American exceeds his/her annual risk of rabies from any source.
Because even sick bats almost never bite, except in self-defense if handled, the risk of contracting any disease from one is exceedingly low for anyone who simply leaves them alone. In Austin, Texas, thousands of people gather nightly to observe the spectacular emergences of 1.5 million bats close-up. And in decades of this exceptionally close association, no one has been attacked or contracted a disease.
Post-exposure rabies vaccinations in the United States are outrageously overpriced, currently costing from $10,000 to $22,000 per person treated. With huge profits at stake, and our CDC heavily influenced by drug companies, promotion of exaggerated fear is not surprising. Unprovoked bites are exceedingly rare, so much so that I have yet to experience one despite close association with millions of bats worldwide for more nearly 60 years.
Human rabies cases are often diagnosed post-mortem or after the patient is incoherent. Even in cases in which parents or friends report bites, the U.S. CDC reports “no bite history” unless the patient is able to confirm. Consequently, human cases, regardless of animal origin (i.e. bat, dog, skunk or raccoon) often get reported as having no bite history. Huge misrepresentation occurs when such reports are used to disproportionately frighten people of bats.
Since 1996 the CDC Advisory Committee on Immunization Practices has advised consideration of post-exposure prophylaxis for “persons potentially exposed to bats even where a history of physical contact cannot be elicited,” unless prompt diagnosis excluded rabies. Based on its independent analysis Canada’s National Advisory Committee on Immunization, opted not to follow CDC’s recommended bat policy. They do not advise vaccination unless there has been direct contact. For detailed documentation, see Rabies in Perspective.
At Merlin Tuttle’s Bat Conservation we’re overjoyed to finally launch our membership campaign. Members at the Leadership level or above were given priority invitations to view the famous Congress Avenue Bridge bat emergence with Merlin aboard a chartered Capital Cruises boat. We all gathered at the Hyatt Hotel’s lounge for drinks (and queso) and to meet and get acquainted. The first member to sign up for the cruise was Janell Cannon, the author of the classic children’s book Stellaluna. Janell graciously signed copies of her book, which is celebrating its 25th anniversary!
The Texas Department of Transportation (TxDOT) has set world records when it comes to helping bats, and that special help is paying big dividends for Texans and for countless visitors. Thanks to the enthusiastic early leadership of Supervising Bridge Engineer, Mark Bloschock and the continuing efforts of Stirling Robertson, now in charge of Strategic Projects, and John Young, an Environmental Specialist, TxDOT is taking great pride in its accomplishments.
On August 21, Stirling and John organized a special bat evening for 30 of TxDOT’s most important media and public information officers. They each received a copy of Department’s new guide to bat watching at state bridges, attended my 20-minute presentation at TxDOT headquarters, then joined me for a special Congress Avenue Bridge bat watching evening. We were delighted when we learned that Mark, who is now retired, would be able to join us.
The bats performed beautifully, and Stirling reported, “There has been overwhelming positive response to your talk and the whole event. Good stuff!” A big thank you to Stirling for making this event possible! We look forward to future collaboration and many more bats in Texas bridges.
Wildlife Disease Association St. Augustine, Florida 8/10/18
By Merlin Tuttle
The Wildlife Disease Association hosted a panel discussion on vampire bats (Desmodus rotundus), their impact, status, and changing distribution on August 5, 2018. A panel of six speakers from Europe, Mexico, and the U.S. were invited to speak. In the lead-off, tone-setting presentation,
I outlined the global value of bats, with special emphasis on Latin America, then proceeded to discuss my decades of observations on vampire control and the enormous damage done when beneficial species are inadvertently targeted. I favored control limited to the vampires causing problems. However, I emphasized that vampire problems are two-fold. One of course involves feeding on livestock and occasionally humans. The other involves their potential impact in crowding other species out of already declining roosting options. The dramatic expansion of vampire populations due to livestock introduction is likely impacting many other bat species that are essential to healthy ecosystems.
During my early bat surveys in remote rain forests inhabited only by aboriginal Indians, I rarely encountered vampire bats. In fact, I do not recall ever having seen a Yanomamo Indian bitten, despite their habit of sleeping nude in lean-to shelters without mosquito nets. I first encountered significant numbers of vampire bats where Indians under European influence were keeping chickens, pigs, or other livestock. My anecdotal observations indicated that humans first became substantial targets when they began keeping pigs or chickens. Vampires became accustomed to feeding on these, and when they were slaughtered for feasts, the hungry bats turned to humans. Later when ranchers sold livestock, again suddenly reducing the food supply, vampires whose numbers had grown to depend on their herds, turned to people.
Only three species of vampires exist. All live only in Latin America, and only one, the common vampire, poses a significant threat to human interests. More than 350 other species are highly beneficial, keeping insect populations in check, pollinating flowers, and dispersing seeds.
For decades, bat biologists have debated the extent to which bats prey on, and potentially reduce mosquito populations. However, recent research suggests bats may be eating far more mosquitoes than yet suspected. Amy Wray and associates (2018) relied on newly refined techniques that provide greater sensitivity.
They tested guano samples from 22 locations in a range of habitats, across the State of Wisconsin, from May 17 through July 29. Seventy-two percent of little brown myotis (Myotis lucifugus) samples contained mosquitoes representing 15 species, more than twice as many as big brown bats (Eptesicus fuscus). But even the larger big brown bats, previously thought to feed mostly on beetles and moths evidenced mosquito-eating in 33 percent of samples. Mosquito-eating remained constant throughout the active season in big brown bats but declined slightly in little browns.
Nature Nights at the Lady Bird Johnson Wildflower Center is a free family-fun event held each summer. Merlin Tuttle and Lucas Miller were the main entertainment for Nature Nights: BATS! on June 21st. Merlin’s bat photographs captivated the children and their parents alike. Afterwards, Lucas Miller, “The Singing Zoologist,” performed for the crowd with his “silly songs about serious science.”
Live bats, courtesy of Dianne Odegard and Lee McKenzie from Austin Bat Refuge, were a big hit.