Matt Jaffe

When a nectar-eating bat pees on your head, it’s not nearly as unpleasant as you might think.

That’s a sentence I never expected to write, probably because it was a sensation I never expected to experience. But as waves of lesser long-nosed bats wing through the darkness and feed at nectar dispensers within inches of where you’re sitting, the chances of rain, if you will, are pretty high. And in fairness, Ted Fleming, a world-renowned bat expert, did warn me of this professional peril seconds ahead of time.

“Don’t worry; it will actually be kind of sweet,” Fleming said. He was right, too.

Fleming was staked out in the backyard of a house in the Tucson Country Club area along with Meghan Murphy, a graduate student at the University of Western Ontario. She had set up video cameras and a microphone array to record the bats in three dimensions as they came in to eat at hummingbird feeders. It was part of a study on echolocation, the ability to identify and find objects by using reflected sound. Echolocation is not part of my skill set, so I stumbled through the blackness in search of a place to sit, unable to see Fleming’s face even though he was just a few feet away.

It didn’t take long to realize that the three of us were hardly alone. Before getting drizzled, I felt rushes of air as squadrons of three or four bats flew to the feeders, lighting on them for just an instant. Then there was the soft swish of beating wings, kind of a fwww fwww fwww sound, as the bats quickly disappeared back into the night. 

Bats don’t usually approach humans so closely, but “leptos” (derived from their scientific name, Leptonycteris yerbabuenae) are not your average bat. Of Arizona’s 28 bat species, the lesser long-nosed bat is one of only two (the other is the Mexican long-tongued bat) that rely primarily on nectar and pollen.

After migrating north from southwestern Mexico along what are called nectar corridors, timing their journeys with the peak blooming season of columnar cactuses, these bats arrive in Arizona by spring to feed from saguaro and organ pipe cactus flowers and, as the summer progresses, agaves at higher elevations. During May, they give birth in maternity caves in Southwestern Arizona and typically remain in Southern Arizona through mid-October before returning to Mexico.

Leptos transport pollen from flower to flower as they eat, so in the world of Arizona pollinators, avian mixed metaphors notwithstanding, the nectar-eating bats are the ugly duckling to the hummingbirds’ swan. Not that everyone agrees with that assessment.

“I actually think they’re quite beautiful,” Fleming says. “Their coats are a nice tawny brown, sometimes almost a honey color. They’re also quite gentle to work with. I’m able to handle them without gloves.”

There are bat people and non-bat people, with the second group by far the larger of the two cohorts. By any measure, Fleming is a bat man. A native of Michigan, he was a self-described “snake chaser” with an interest in reptiles and amphibians. “As a kid, I liked nature right from the start,”
he explains.

While in graduate school at the University of Michigan, Fleming traveled to Panama to research rodent populations and also began working with bats. Intrigued by his findings, the National Science Foundation offered to support his bat studies, and soon Fleming shifted his emphasis to these flying mammals. “I wasn’t born to work with bats, necessarily, but bats became very interesting to me,” he says. “Just the diversity and abundance. Man, in some places I could stand under a fruiting fig tree and watch all of these bats swarming. It was amazing to see them in action.”

At the time, not many biologists focused on tropical bats, and because the animals’ lives were so dependent on specific plant species, Fleming had to become an expert in both. “The hours were tough,” he says. “I routinely did 18-hour days. I worked on plants during the day and the bats at night.”

Every summer for 16 years while he was at the University of Missouri and the University of Miami (where he now is an emeritus professor of biology), Fleming traveled to Costa Rica to study fruit-eating bats. He also spent time in Australia, where he and his wife, Marcia, adopted a trio of orphaned black flying foxes — that continent’s largest bat, with wingspans of more than 4 feet.

Then, in 1988, Merlin Tuttle, the founder of Bat Conservation International, asked Fleming if he wanted to trade the rainforest for the Sonoran Desert and study leptos, which had been newly listed as an endangered species, as pollinators of columnar cactuses. “I thought about all of the cool things that might be going on in the desert, based in part on my memories of Disney’s The Living Desert,” Fleming says. “I saw it as a kid, and those nature films were really influential. So I said, ‘Yeah, it sounds cool. I’ll give it a try.’ Boy, I never looked back.”

Photograph by Bruce D. Taubert
Two lesser long-nosed bats approach a hummingbird feeder. The bats have become more common at Tucson feeders in the past decade. | Bruce D. Taubert

For most of my life, I have been bat agnostic — that is, until hummingbirds proved to be my gateway pollinator to leptos. A few years ago, while in Southeastern Arizona, I heard several hummingbird experts describe how bats drained their feeders during the night. That didn’t square with my understanding of what bats ate. Bugs, certainly; fruit, too, and, notoriously, blood for the world’s three kinds of vampire bats (none of which live in Arizona). But along with the birds and the bees, there were also, apparently, bats.

At first it was difficult to picture bats, those denizens of the dark, flitting among the flowers. After all, plenty of the world’s more than 1,300 kinds of bats (about a quarter of all mammal species) resemble gargoyles come to life, as if they flew straight out of a closet of nightmares. Some — like ghost-faced bats, whose range includes Arizona — are just plain weird.

The Arizona-Sonora Desert Museum’s website gamely tries to capture the appearance of ghost-faced bats: “They probably get their name from their unusual-looking face. Their large ears are rounded and join at their forehead. This makes their small eyes look like they are actually in their ears. They also have leaf-like skin flaps protruding from their chin.”

By comparison, leptos are Smurfs with wings. Unlike ghost bats, leptos have defined features: bright, alert eyes; mouths that curve up into what we perceive as smiles; and long snouts tipped with upturned nose leaves that give them an impish, Pixar-ready quality. They are great athletes, too, muscular little creatures that fly 25 miles from their day roosts to stop at feeding areas.

Although they boast 14-inch wingspans, leptos weigh only about 0.8 ounces. While similarly sized mammals, such as rodents, have short life spans, leptos routinely live six or seven years. They don’t reach sexual maturity for two or three years, and then they give birth to only one pup annually, a reproductive strategy more typical of much larger mammals. 

With enormously long tongues featuring brushy tips and small teeth, leptos are well adapted to their nectar-and-pollen diet, which is supplemented by cactus fruit and insects. Considering the high sugar content of what they eat, leptos are remarkably resistant to diabetes and tooth decay, Fleming says. They’re the main pollinators of cardon cactuses, a prominent columnar species in Mexico with nectar three times more sugary than Coca-Cola. Fleming says that even though blood-sugar readings do spike while leptos eat, they quickly drop back to normal levels. But, like any bat, leptos are not without mystery. “There’s still a lot we don’t know about the basic biology of lesser long-nosed bats. Which makes them fascinating,”
Fleming says.

Since 2007, a network of “citizen scientists” in the Tucson area has helped add to the data that experts like Fleming draw upon in trying to understand leptos’ behavior. Bats foraging at hummingbird feeders in Southeastern Arizona, including eastern sections of Tucson, was nothing new. But after a poor season for agave flowers in 2006, leptos started to visit feeders throughout the Tucson area.

Under the auspices of the Arizona Game and Fish Department, the U.S. Fish and Wildlife Service and the town of Marana, locals were enlisted to keep track of bat behavior and feeding patterns in their backyards. Now, this network of citizen scientists has grown to around 100, says Janine Spencer, environmental-projects manager in Marana.

“Our volunteers love watching the bats and want to be the first ones to report them at the feeders at the start of the season,” she says. “It’s so much fun to go out on the back porch and see them zooming all around. With all of the bats in the air, it’s like swimming in the ocean among fish.”

Spencer says the bats at her house go through about a quart of nectar per night. One participant, however, quit the program when the bats’ appetites became too much. “He was putting out a gallon of sugar water every night,” she says. “He just kept trying to keep the feeders filled until one day he finally said, ‘I give up.’ ”

In 2013, program participants first reported bats feeding west of Interstate 10, and radio-telemetry tracking has revealed a new day roost in the Santa Catalina Mountains. But some basic questions remain unanswered, Fleming says. For one thing, virtually all the leptos that visit feeders are juvenile or yearling females. 

“When we started looking at the feeders, I would have expected that adults would be as common as juveniles,” Fleming says. “But apparently the youngsters are finding these feeders in the absence of teaching by adults. And it’s not like the juveniles are roosting around the corner and these feeders are their closest food sources. They’re foraging over huge areas.”

Another question that arises: Why are leptos expanding their activities in urban areas? Fleming says it’s unclear whether the rate of agave blooms has been fluctuating. “There’s something driving the bats into the city more and more because there’s something changing outside the city,” he says. “But who knows what it is.” 

After a couple of hours, the leptos appeared to be done for the night, and I said my goodbyes to Fleming and Murphy before making my way through the darkness. I drove back to my sister’s house in the Catalina Foothills. It was two nights before the new moon. Bolts of lightning split the September sky, and thunder rumbled in the distance. Perfect bat weather, I figured, before settling in on the deck next to the hummingbird feeders, hoping that some unannounced guests would pop by, hungry for a midnight snack.