On a late summer evening in 2019, a small, flat-bottomed riverboat pulled away from the south shore of Austin’s downtown waterway, Lady Bird Lake. Its destination: the Congress Avenue Bridge, whose underside is home to 1.5 million tiny, fuzzy free-tailed bats. The boat’s passengers scanned the eastern horizon as the sky faded to a deep, slate-y blue. In a minute a call went up: “There’s one!” Then there was another, then twenty, and in a few minutes thousands, a swoosh of wings as the bats flew off to feast on insects over the farms and fields east of the city.
Back on the bat boat, the passengers—myself among them—strolled around chatting and sipping plastic glasses of the mezcal that someone had thoughtfully supplied. Then a few people squeezed around a table to hear the evening’s guest speaker, a small, balding man with glasses and a professorial manner. Clearing his throat, he began to talk, quietly at first, then with mounting enthusiasm. “Bats are absolutely essential to the ecological and economic health of the world,” he said. “Here in Texas, for instance, they feed on moths whose larvae threaten corn and tobacco. They save millions of dollars in pesticide application. Why, the bats that live under the bridge can eat up to ten tons of insects a night.”
He pivoted to another bat benefit: pollination and seed dispersal. “Hundreds of tropical fruits depend on bats, including mangoes, guavas, and wild bananas.” In Mexico, he added, bats pollinate wild agaves, the relatives of the cultivated plants used to make tequila and the mezcal we were drinking.
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The bespectacled speaker was internationally known bat expert Merlin Tuttle, and at 78, he’s clearly still as beguiled by the flying mammals as he was as a boy exploring bat caves in Tennessee. He had gone on to earn a PhD in bat ecology, and in 1982, he founded the educational organization Bat Conservation International. Under his leadership, the group—which moved from Milwaukee to Austin in 1986—undertook a massive and successful program of bat public relations. Rabies was a great fear at the time, and Tuttle—nicknamed the “Bat Man”—repeated tirelessly that fewer than 1 percent of bats carry the disease. He also showed the city how to exploit the tremendous tourism potential of the bats living under the bridge. It took time, but BCI changed the flying mammals’ image from reviled vermin to adorable city mascot.
There were occasional setbacks, however. One of the most significant was the outbreak in 2002 and 2003 of Severe Acute Respiratory Syndrome (SARS), caused by a virus that many scientists suspected was harbored by bats in the wild. Ultimately, researchers found that the disease leapt from bats to civets—mongoose-like animals that are sometimes eaten in China—and then from civets to people. Bats were not the direct cause. But to Tuttle’s great distress, many people began to associate bats with a near-pandemic. Bat fear had taken on a malevolent new form.
With time, though, SARS faded from the front pages. And in 2009, after nearly thirty years as executive director of BCI, Tuttle retired. A few years later, he created his own organization, Merlin Tuttle’s Bat Conservation, and filled its website with scholarly video lectures and thousands of his excellent close-up photographs (he even had to gently shampoo the occasional rumpled bat). He also became an ever-more-ardent defender of bats. Any publication that implied that they were inherently dangerous was likely to get a polite but stern letter. But, all in all, things were quite peaceful until the end of last year. Then came the coronavirus pandemic.
The emergence in December 2019 of the new disease initiated a desperate hunt for its source. Scientists compared the current virus with stored samples of the SARS virus—it is also a coronavirus—and they found similarities. The search for the first infections led to a seafood and wild animal market in Wuhan, China. It was filled with numerous animals being kept, and often slaughtered, in far from hygienic conditions. Bats are sometimes sold in such markets.
Because I had met Tuttle the year before and because I was curious about his take on the bat connection, I called to ask his reaction. He had a lot to say. But basically, it boiled down to this: he feels the world is rushing to judgment to convict the critters on evidence he doesn’t find totally persuasive.
To begin with, he said, it has not been definitely established that bats were being sold in the Wuhan market. The U.S. Centers for Disease Control and the World Health Organization could not confirm that bats had been there. In Tuttle’s opinion, the often-mentioned coronavirus-carrying pangolin, or scaly anteater, is a more likely intermediary. (The details are complex, but basically the form of the pangolin coronavirus has a structure, called a spike protein, that renders it more capable of invading a human cell.) However, the presence of pangolins at the market was also disputed.
In any case, he also thinks that viruses in bats are being overstudied. In particular, he believes that some of the large grants that often go to scientists who focus on bats would be better spent looking for intermediaries, such as civets in the case of the SARS outbreak. He also pointed out that the virus that causes MERS (Middle East Respiratory Syndrome) jumped from dromedaries to people. In the case of the Hendra virus, horses were the go-between.
His second and broader point was that, in the end, the true problem is human beings. “In America,” he told me, “old-growth forests once provided countless tree hollows where bats could roost. Yet very few such forests remain. In Southeast Asia, caves, sometimes with a million or more bats, have been destroyed by careless limestone mining.”
In this opinion, he aligns with many others. Disease ecologist Jonathan Epstein with EcoHealth Alliance has said, “How do these viruses emerge? It’s human activities,” as people clear land for agriculture and move into pristine habitats. But both things can be true at once, Epstein argues: bats can sometimes play a role in virus transmission, and they’re also a vital part of the ecosystem, deserving of conservation and respect.
Immunologist Michelle Baker, with CSIRO, Australia’s national science agency, observed, “These wet markets have been identified as an issue because you do have species interacting.” She went on to say the dangers need to be highlighted and the markets perhaps clamped down on. Does Tuttle think that suggestion will be heeded? He doubts it, but focusing on human collusion is a step in the right direction. So is educating people about the good that bats do for the environment and the economy.
For now, Tuttle—like everybody else—is waiting for a vaccine or a cure. In the meantime, he continues to challenge those who libel the good name of bats. He also looks forward to the day when people can again board a small boat on Lady Bird Lake and raise a glass of mezcal as they watch a gazillion bats disappear into the night sky.