The Mexican free-tailed bat (also known as the Brazilian free-tailed bat) is the most prevalent species in the UF colony — Photo courtesy of Florida Museum of Natural History
Without bats, there’d be no tequila.
So, with Cinco de Mayo less than a month away, you might consider toasting the world’s only flying mammal on April 17, which is National Bat Appreciation Day.
You might also consider a trip to see these incredible creatures – roughly 500,000 of them! – as they emerge from the bat houses at Gainesville’s University of Florida, the largest colony in the world living in purpose-built structures.
Paul Ramey is the assistant director of marketing and public relations (and bat advocate, his e-mail signature states!) for the Florida Museum of Natural History – also on the UF campus – and he fields countless inquiries from local and out-of-state visitors eager to watch the nightly show.
And what a show it is.
Come dusk, the sky deepens to a lovely lilac and as spectators gather beyond the fence line at the bat barn and houses – three 16 x 16 structures, one of which remains unoccupied (more on that later) – and the evening commute begins.
At first a trickle, errant bats emerge from beneath the roof lines, leathery wings flapping in that signature chaotic style so different from that of birds, and stream out to hunt insects in flight. Some head straight for the onlookers. weaving flawlessly between them – sometimes inches away. It surprises and terrifies some, but it’s only happenstance.
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Bats, of course, are not the bloodsuckers that lore has made them out to be – but they sure do love eating them. The UF colony consumes 2,500 pounds of insects every night! And the gathering of humans, breathing as they do, has drawn out scads of mosquitoes. The first flyers to emerge are happy to snatch these biting pests as they flit amid their own human buffet.
"There is no bat species that specifically targets mosquitoes," Ramey explains, noting that the UF campus is hardly mosquito-free. "But all of our bats are insectivores...and help reduce the numbers."
Sleep well, night flyers; bats are designated by Florida Statutes Chapter 372 as "Non-Game Wildlife" and their habitat must not be disturbed by humans — Photo courtesy of Kristen Grace/Florida Museum of Natural History
Fans of the bats, myself included, love the proximity to these delicate and oft misunderstood creatures of the night, but it’s those who feel differently we can thank for the bat houses in the first place. Back in 1987, when a campus building burned to the ground, the displaced colony took up residence in other structures, including UF’s hallowed home of the Gators.
Fans attending sporting events, including then-Governor Bob Martinez, were not comfortable sharing their space with the bats.
"They didn’t like being able to smell them or hear them, or being close to them when they emerged in the evening. And obviously, they didn’t like having the guano (that’s bat scat) dropping to the ground."
Concerned parties stepped in, and with additional funding from the nearby Lubee Bat Conservancy and some construction donations, the UF Athletic Association paid to have the first bat house built.
And there it sat. Empty.
Turns out, says Ramey, "you can tell a bat where not to live, but not where to live."
For three-plus years, UF employees worked on excluding the bats from the stadium and other buildings.
"Eventually," says Ramey, "there were fewer buildings the bats could access and in 1995, the bats stayed [in the house] after having their pups and the colony continued to grow – and grow – and grow!"
The colony is mostly made up of Mexican free-tailed bats, a very communal species that prefers living in man-made structures. A second structure, the first barn, was built in 2009 and occupied the following year. In February 2017, the new bat barn was added – the original 1991 house has essentially lived its lifespan – but the fickle bats have not yet moved in.
In the foreground, the second bat house, built in 2010; the new one behind it is thus far vacant. — Photo courtesy of Kristen Grace/Florida Museum of Natural History
"The hope was that the bats would occupy the new structure that same year and then the original structure could be taken down."
UF staffers are now in wait-and-see mode; there’s no timeline for eviction.
Although UF maintains the houses and manages the bat waste (in the past, the guano – four 55-gallon drums' worth – was given away monthly to farmers, who prize it as high-nitrogen fertilizer; it is now used by the UF Field and Fork program for their gardens), the bats are 100 percent wild.
And as they prey on the insects, so, too, do they become prey. Among the nightly visitors are hawks, who attempt – mostly unsuccessfully, the bats are truly exceptional acrobats – to snag a few as they emerge for feeding time.
"I have received calls from citizens upset about the hawks, complaining that UF should 'do something' about them," says Ramey. "Some people say it’s cruel that we allow them to hang around." But through public outreach and social media efforts, he notes, the complaints have declined significantly over the past several years.
"The bats are wild and so are the hawks, and the hawks also must eat to survive. It’s part of nature."
The hawks’ best success, Ramey points out, comes during maternity season, when pups sometimes fall from the structure and the raptors are able to pick them off. The birds do up the drama factor come evening time, though, with spectators gasping and cheering as the tiny flyers evade the feathered hunters.
Spring and early summer, as the days increase in length, are the best seasons for observing the emergence. They appear sooner after sunset, when twilight lingers longer. Like many Floridians, the bats tend to grumble and stay in when temps dip below 65.
Ramey, who gives regular outreach presentations, has trouble keeping them to an hour when attendees begin asking questions.
"From the bumblebee bat, that is little more than an inch long and weighs about as much as a penny to the flying foxes, fruit bats that weigh more than two pounds and have five-to-six-foot wingspans – the amount of diversity in bats is astounding!"
In fact, bats are the most common mammal in Florida.
"They play an important role for us by saving the agriculture industry billions of dollars annually in reduced pesticide costs. And in other parts of the world, they play a key role as pollinators."
Which brings us back to Mexico, where several bat species have co-evolved along with agave over thousands of years. They are the plant’s primary pollinator, responsible for its hardiness and diversity.
With tequila high in demand, many commercial producers have turned to cloned agave, which is vulnerable to disease and fungus. Some use chemicals that harm the bats, several of which are already endangered.
So, if you can’t visit UF for Bat Appreciation Day, do the next best thing: buy a bottle of bat-friendly tequila (check out the work of the Tequila Interchange Project) and raise a glass to these delicate little night flyers.