Bats are often seen as threatening – especially lately, as scientists have suggested a connection between a bat species and the coronavirus pandemic.
But to bat biologists, such fear is misguided. Not only are there more than 1,400 different species of bats, but many bats play vital roles in their ecosystems.
In the tropics, where all kinds of bats are often killed out of fear of vampire bats, fruit-eating bats have been found to play a key role in pollinating rainforests.
In North America, some insectivorous bats may be vital to agriculture. Researchers estimate that losing bats across the continent could have an economic impact of agricultural losses perhaps more than $3.7 billion a year.
But researchers say there is also inherent value in understanding bats, regardless of what they do for us. “They represent kind of the pinnacle of evolution in my mind,” says Joy O’Keefe a wildlife biologist at University of Illinois at Urbana-Champaign. “The fact that they can fly and that they use echolocation to navigate at night in the dark is remarkable. Bats are just super cool, and we know so little about them, and we have so much to learn from them.”
Often associated with darkness, bats have long been vilified in Western culture. And now scientists’ claims that a species of bat likely played a role in the origin of the coronavirus pandemic hasn’t helped their popularity.
But to bat biologists, such animus is misguided. For one thing, bats are incredibly diverse: There are more than 1,400 different species of bats, making up between a quarter and a fifth of all mammal species.
“People really do think of a bat as just one kind of animal,” says Gerald Carter, an assistant professor and behavioral ecologist at Ohio State University.
Bats also play vital roles in the ecosystems they inhabit. By spreading seeds, fruit bats help regenerate rainforests, and by eating insects, insectivorous bats help protect plants – including crops – from pests. When it comes to bats, say scientists who study them, we’ve got it all wrong.
“Bats are ecologically just really important,” Professor Carter says. “They provide billions of dollars’ worth of ecosystem services to people.”
So what exactly is a bat?
“Bats are the mammals that can fly,” Dr. Carter says, and, besides sharing a common ancestor, that’s all that unifies all bats.
Counter to the popular image of bats, not all of them are nocturnal. A few bat species have been observed searching for food during the day.
Bats don’t all look like one another either. Some are massive, like the Philippine golden-crowned flying fox, whose wingspan stretches more than 5 feet. Others are tiny, like the inch-long Kitti’s hog-nosed bat, also called the bumblebee bat.
And although the horror-story view of bats often depicts them as blood-sucking, bat diets are extremely varied from species to species. While some do feed on blood, many munch on insects or fruit, and one kind of bat even eats fish.
Vampire bats draw perhaps the most ire. And although they can be reservoirs for disease, the way that humans that live near them often respond is to try to eradicate all the bats around, says Dr. Carter. And that can create more problems.
A 2013 study found that reducing vampire bat populations may actually increase rabies cases, likely because of a sort of herd immunity in some populations. When bats are killed off indiscriminately, Dr. Carter explains, more individuals from farther afield will be moving around and interacting with one another, thus bringing more disease into a given population.
We know that bats are really sensitive to disturbances, says Joy O’Keefe, assistant professor and wildlife extension specialist at University of Illinois at Urbana-Champaign. So between eradication and habitat loss, bats are probably getting less and less healthy more broadly and that is increasing the likelihood of them being disease spreaders.
It’s not all about disease, though. Those bats that eat insects or fruit also play key roles in agriculture and the broader ecosystem.
In the tropics, where all kinds of bats are often killed out of fear of vampire bats, fruit-eating bats have been found to play a key role in rainforest regeneration. Their diets help disperse seeds of a wide range of plants.
Snacking on crop and forest pests in North America, some insectivorous bats may be vital to agriculture as we know it. Researchers estimate that losing bats across the continent could cost $3.7 billion in agricultural losses.
Dr. Carter’s enthusiasm for bats goes beyond their benefits to people and the broader ecosystem.
“I just love bats so much,” he says. “It’s a real deep-down thing.” He compares vampire bats – the main subject of his research – to wolves.
“Right now, people really value wolves. They put them on T-shirts, they say wolves are really majestic, cool, smart, and socially charismatic animals,” Dr. Carter says. “But for a long time, people wanted to just eradicate wolves because the entire idea that we had of a wolf was that it was just terrible for ranchers and that they were really aggressive and nasty.”
And, he says, to someone who studies them, vampire bats are all those same things, too.
Dr. O’Keefe agrees that there is inherent value in understanding bats, regardless of what they do for us. “They represent kind of the pinnacle of evolution in my mind,” she says. “The fact that they can fly and that they use echolocation to navigate at night in the dark is remarkable. Bats are just super cool, and we know so little about them, and we have so much to learn from them.”
Bats aren’t just diverse in how they eat or where they live or what they look like, too. They also have rich social lives that are incredibly varied among species, Dr. Carter says. For example, vampire bats – his subject of study – have very individualized relationships with one another, much like humans have distinct friendships. They display altruism by feeding and grooming one another, and those relationships seem to be reciprocal even among non-kin.
There’s also a bat social system that seems unique in the animal kingdom: social groups entirely made up of unrelated individuals. Scientists still don’t quite understand why the greater spear-nosed bat forms such groups, Dr. Carter says, but the bonds among group members seem to be quite strong. When a young pup falls from the roost, other groups will try to attack it, but females – even unrelated to the pup – will guard it.
Over the last couple of decades, bat biologists and conservationists have made a concerted effort to change the perception of bats. A big push came with the discovery in the 2000s that white-nose syndrome was decimating North American bat populations. In fact, says Dr. O’Keefe, some of the funding to save the bats across the U.S. was specifically allocated to outreach efforts to engage and educate the public about the importance of bats.
There have been children’s books like Stellaluna, scientists have worked with farmers to understand the role bats play in their fields, and bat biologists have hosted events and visited schools and libraries to foster a culture of appreciation for bats.
And it seems to be working, says Dr. O’Keefe, who was formerly director of the Center for Bat Research, Outreach, and Conservation at Indiana State University.
“Certainly in North America, we have made really serious inroads in bat conservation and in people’s perceptions of bats,” she says. “I don’t know if you’ve noticed that in the supermarket or wherever you go and see Halloween stuff, but over the years, we’ve all noticed that there’s been a big shift toward these smiling bats instead of bats with scary fangs and glowing red eyes. You don’t see that as much anymore.”