May 2, 2022
A tight cluster of Indiana bats hibernating on a cave ceiling. Photo by Ryan Hagerty, USFWS.

What’s the Deal with Bats and Coronavirus?

By Tara C. Hohoff
A colony of bats fly towards a sunset. Silhouetted hills are in the background.
Bats flying into the Texas sunset. Photo by Ann Froschauer, USFWS.

As a bat biologist, this is becoming a regular question in my life as emerging research links bats and the virus that has rapidly consumed our lives. It should be noted that we still aren’t sure if bats were the animal that transferred the virus to humans, but genetically SARS-CoV-2 (the virus that causes COVID-19 in humans) is related to coronaviruses detected in horseshoe bats in Yunnan, China. However, scientists that study viral relationships have determined that there are likely missing links (unknown viruses that occur in wildlife) between the bat virus and the human SARS-CoV-2 virus. Unfortunately, this connection has made some people who already had negative associations with bats, feel even more strongly opposed to these nighttime creatures. There are so many reasons to appreciate bats, but this situation highlights that we have a lot to learn about how many species of bats can survive these types of infections. Understanding how their immune system responds to minimize inflammation could change how we treat infectious diseases in humans.

A large brown bat roosts on a lichen covered tree branch.
Wahlberg’s epauletted fruit bat roosting on a branch. Photo by Susan Ellis,

The reason we do so much outreach with the Illinois Bat Conservation Program is that the news tends to sensationalize the negative information about bats and we want to provide avenues for the public to learn all the fascinating facts about bats. First, bats are an incredibly diverse taxon of mammals with at least 1,400 known species worldwide. Being mammals means that they give birth to live young and nurse their pups. Many Illinois bat species roost in dead trees under loose bark but around the world you can find bats in a wide range of habitats, including the Honduran white bat which builds its own leaf tents. Bat diets are also diverse. Illinois bat species are all insectivores, many of which help to reduce backyard pests such as mosquitos and control agricultural pest insects that damage crops. A few species that reside in the U.S. desert southwest feed on nectar and assist plants with pollination. Bats worldwide are important pollinators, especially for the agave plant used to make tequila which is predominately pollinated by bats. In Mexico and parts of South America you can find bats that fish for their food. The large flying foxes that have bigger eyes and smaller ears are fruit eaters, using keen eyesight instead of echolocation to find ripe fruit and providing the important ecosystem service of dispersing seeds.

Bats do not choose to interact with humans. As we plan for the future on how we can avoid an outbreak like this, it is important that we focus on how humans can avoid these situations. If we left wildlife alone, our risk for infectious outbreaks would be significantly reduced. We displace bats from their habitat for development around the world (and then wonder why they are in our attics). We harvest bats from the wild to be sold in markets along with many other at-risk species. It is awesome to be interested in the natural world (I have made a career out of it!), but I hope this experience reminds us of the need to respect boundaries between humans and wildlife.

A small wooden box open on the bottom for bats to roost in is installed on the side of a blue shed. Tree branches are against a partly blue sky in the background.
A bat house installed on the side of a backyard shed. Photo by Sarah Marjanovic.

So, what can you do? Most important is to learn more and spread the positive information you learn about bats. Bat Conservation International is an amazing resource for adults and children. Other suggestions include:

  • Planting flowers in your yard this spring that will attract moths, which are likely a large part of bat diets in Illinois.
  • Avoiding the use of insecticides which reduce prey available for bats and try to keep water sources clean, bats need to drink water, too.
  • If you own a pool, consider installing a wildlife ramp in case bats, frogs or other wildlife get stuck.
  • Keeping cats indoors. Domestic cats have a significant impact on wildlife, including birds and bats.
  • Making sure your house is well sealed with any openings or vents (especially in attics or chimneys) covered with screen so that bats can’t get in.
  • Leaving dead or dying trees on your property, if possible and without risk to your home or human safety, for bats and other wildlife to call home.
  • Additionally, you could install bat houses in your yard.
  • Register your bat house with Illinois Bat Conservation Program

Tara Hohoff is the Project Coordinator for the Illinois Bat Conservation Program and an Associate Mammalogist with the Urban Biotic Assessment Program.

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