6 reasons why bats aren’t enemies: They help make tequila, and other surprising facts you may not know

Anderson Cooper examines the possible connection between bats and many deadly human viruses in CNN Special Report “Bats: The Mystery Behind Covid-19.” Watch Sunday at 10 p.m. ET/PT.

Bats have shouldered much of the blame in the quest for the origins of the novel coronavirus.

In March, researchers published a study that found a 96.2% similarity between the coronavirus that causes Covid-19 and a virus found in a horseshoe bat from China’s Yunnan province.

“Ninety-six percent is a different virus; it’s a bit like the difference between us and chimpanzees,” Peter Daszak, the president of the non-profit EcoHealth Alliance, explains in CNN Special Report “Bats: The Mystery Behind Covid-19.”

“It’s a different species of virus. But what it tells us is where the virus probably came from. It means that SARS-CoV-2 probably came from bats and probably in Southern China.”

Yunnan province isabout a thousand miles from Hubei province, which is where the city of Wuhan saw the early virus outbreaks.A mix of potentially infected wild animals in a wet market could have caused the virus to jump from animals to humans. But zoologists, ecologists and disease experts have said that it’s human behaviors — such as destroying natural habitats — that might be to blame for the transfer of the disease.

Overall, bats have caught a bad rap — not only with their connection to Covid-19 and other virus outbreaks but in cultural symbolism as well. Bats have been associated with vampires, darkness, evil, witchcraft and death.

However, as experts tell Anderson Cooper in the CNN special report, these flying mammals have a crucial role in our ecosystem, and there are many unique facts that the average person likely doesn’t know about them — including how they help produce tequila.

They save us from mosquitoes

Bats play a large role in the ecosystem by controlling insect populations, said Nancy Simmons, American Museum of Natural History mammalogy curator and coauthor of “Bats: A World of Science and Mystery.”

DSCN0860—One of the new bat species. We found Hipposideros caffer (Sundevall's leaf-nosed bat) to consist of 8 distinct lineages; 3 of these (including this bat) appear to be new to science (photograph courtesy of B.D. Patterson/Field Museum)

Related article Newly discovered bats are related to those associated with the pandemic

In an hour, a normal-sized bat can eat up to 500 to 1,000 mosquitoes, which can carry diseases such as the Zika virus, dengue fever or malaria.

Their insect-eating habits also save big money for agriculture. For the US economy, bats are worth over a billion dollars every year “in terms of how many pesticides we don’t need to use and how much more food we get,” said Dan Riskin, a Canadian evolutionary biologist and television host.

The Mexican free-tailed bat of Texas eats a great number of moths, protecting the corn crops of the region.

They’re intrinsically environmentally conscious

Pest control isn’t bats’ only contribution to our ecosystem. The waste droppings of fruit-eating bats — particularly those in rainforests — disperse seeds, helping to regenerate plants and trees previously damaged or cut down.

Their droppings are also full of nitrogen, which is a vital ingredient for crops since it’s a main component of chlorophyll, the compound by which plants use energy from the sun to produce sugars from water and carbon dioxide. This process, called photosynthesis, generates oxygen. Nitrogen is also a crucial element of amino acids, the building blocks of proteins.

The Smithsonian Institution carries out bat sampling in Myanmar and Kenya, allowing them to discover 6 new coronaviruses.

Related article The virus hunters who search bat caves to predict the next pandemic

And historically, bat caves have been harvested for fertilizer and then explosives during the Civil War. The high nitrate content of their feces provided a key ingredient for the production of gunpowder amid a shortage of supplies.

Cogs in the tequila-making machine

Some bat species serve as the only pollinators of particular types of bananas, mangoes and cacti. The muzzles of long-nosed bats are designed to fit perfectly inside some cactus blossoms, which fittingly only open at night.

This species, whose habitat ranges from the American Southwest to central and southern Mexico, pollinates the blue agave plant — the key ingredient in tequila. They act as surrogates carrying the pollen from one agave plant to another.

“Who doesn’t love tequila, right?” Riskin said. “I mean, just right there, that should be reason enough for people to love bats.”

They’re fighting a disease humans gave them

While we’re fighting a virus that potentially came from bats, they’re fighting a fungus that might have transferred to them from us.

In North America over the past 15 years, populations of about a dozen bat species have been affected by a disease called “white nose syndrome.” In some cases, populations have plummeted by more than 90%.

“It’s a cold-loving fungus that grows on the bat when the bats are hibernating in the wintertime,” Simmons said. “It’s a terrible threat to bats. And ironically, it’s a disease that we brought to bats. This disease is identical to fungus that naturally occurs in Europe. And so the thought is that it was simply brought over by people and was accidentally introduced into bat caves.”

Lacking disease-related genes

When a virus infects our cells, our immune response will recruit immune cells to the site to try to clear the infection, said Cara Brook, a postdoctoral Miller Fellow in the department of integrative biology at the University of California-Berkeley, in the CNN special.

The response that signals uninfected cells to turn on their defense system typically results in inflammation — which, in humans, is often in the form of fever or swelling that helps fight infection.

But bats’ immune systems don’t respond the same way — they’re able to withstand strong immune reactions and have an anti-inflammatory response as well.

Common vampire bat (Desmodus rotundus) in a zoo

Related article How vampire bats make friends before sharing meals of blood

Some bat species “are actually missing the genes that we and other animals have that trigger the inflammatory process” in response to pathogens and viruses that can be deadly for people and other animals, said Jonathan Epstein, a veterinarian, disease ecologist and the vice president of science and outreach at EcoHealth Alliance.

Studying bat immunology could help provide insights regarding possible treatments for the current pandemic, as well as any future pandemic of a bat-related virus.

Bats help pave the road to medical discoveries

Bats already contribute to research that could one day be helpful to humans.

In a 2019 study published in the journal Biology Letters, researchers analyzed evolutionary trees reconstructed from the DNA of the majority of known bat species. They found that four species — horseshoe, long-eared, common and mouse-eared — all live at least four times longer than other similarly-sized mammals.

And when adjusted for size, bats exceed the average human lifespan. The study added to previous research that suggested looking further into bats as models for healthy aging, to find traits and mechanisms associated with a long life span.

Vampire bats in particular — a rare species that lives in Central and South America and feeds on the blood of birds, pigs and cattle — have blood-thinning agents in their saliva, which helps them draw free-flowing blood from their prey. Scientists have looked into whether there are insights about their blood that would be helpful for treating humans.

Some studies have also suggested that vampire bats’ blood might also lend to treatments for conditions including stroke, hypertension, heart failure and kidney diseases.

And now, studying how bats’ immunology enables them to withstand numerous viruses and pathogens could be applied to developing prevention and treatment for humans.