Bats – Helpful, Not Harmful

Bats – Helpful, Not Harmful

Brazilian free-tailed bat (Tadarida brasiliensis) eating a corn earworm moth (Helicoverpa zea).

Brazilian free-tailed bat (Tadarida brasiliensis) eating a corn earworm moth (Helicoverpa zea).

If you think you’d prefer a world without bats, we present to you three reasons to reconsider. Most negative stereotypes about bats are untrue. The reality is that bats benefit us in numerous ways. Here are a few facts that may convince you we should be thankful for bats rather than fearful of them.

 

1. INSECTS WOULD BUG YOU MORE IF WE HAD NO BATS 

Over two-thirds of the 1,240 species of bats that roam the earth’s skies feed on insects. These aerial acrobats cruise over forests, grasslands, waterways, and crop fields, assisting us by consuming nighttime insects. Bats collect insects using a variety of innovative approaches: some scoop them from the air with their wing or tail membrane and transfer them to their mouths; others nimbly pluck insects off surfaces such as leaves, tree trunks, or even water. These bats are our allies, as they drastically reduce the number of pests that would otherwise bite us or damage our crops. It’s estimated that bats help North American farms save around $23 billion a year. If all bats were lost, the resulting damage to crops due to the insects bats formerly kept in check is estimated to be $74/acre across the US.


2. SOME FOODS AND DRINKS MIGHT BECOME RARE IF WE HAD NO BATS

If you like tropical fruits like mangoes, papayas, guavas, bananas, or figs, you should be thankful for bats. Many bats in the tropics and sub-tropics pollinate and disperse seeds in ecosystems ranging from deserts to rainforests. Bats in the desert visit columnar cacti and agaves, ensuring pollination of the plants responsible for making tequila. Bats in the rainforests help regenerate new forests and ensure availability of many locally-consumed and highly-nutritious fruits.


3. BATS CAN HELP US SOLVE MEDICAL PUZZLES

Bats possess many unique biological adaptations that hold clues vital to solving human health issues. Bats have already made notable contributions to the medical community. The special blood thinning enzymes found in the saliva of vampire bats has helped us understand how to prevent blood clotting during open-heart surgery. The adaptations bats have for seeing in the dark are being studied to see if they could provide insight useful for assisting people who have limited vision.

 

Despite the many ways bats help us, they remain misunderstood by many. Fear of bats, called chiroptophobia, is the result of negative stereotypes about bats. Most of these stereotypes are downright untrue. First, there’s a common belief that bats get caught in people’s hair. This is highly unlikely: if a bat is agile enough to catch an insect the size of a gnat in flight, it can certainly steer clear of a human head. Second, there’s a common fear that all bats have rabies. In fact, rabies is quite rare among bats, and much more common among raccoons and foxes in Florida. Third, despite the portrayal in movies of bats as aggressive towards humans, bats are in reality not likely to bother people. In fact, they’re generally far more afraid of you than you are of them.

 

If you’d like to help bats (and perhaps get some free control of insect pests in your area), consider building or buying a bat house for your property. Also consider leaving dead and dying trees in your yard if they’re not a safety hazard, avoid trimming dead fronds off your palm trees, and retain Spanish moss. All of these locations (tree cavities, dead palm fronds, and Spanish moss) offer roosting habitat for bats. By promoting bat habitat, you may boost local bats and find you have fewer insect pests nearby. 

 

Battling Bat Myths

Battling Bat Myths

Close-up photo of a Seminole bat and her two pups. Photo credit: Carrie Stevenson

This close-up photo of a Seminole bat and her two pups exhibits their furry, mammalian traits. Photo credit: Carrie Stevenson, UF IFAS Extension

As we enter Halloween season, one of the most popular images of this spooky time of year is that of a bat. The creepy tales of vampire bats and Dracula are enduring and certainly exciting. Unfortunately, many negative connotations exist around this fascinating species. Perhaps you’ve heard they carry rabies, that they will fly into your hair, or that many of them are considered blood-sucking vampire bats?

In fact, there are many benefits to having bats in one’s landscape, neighborhood, or farm. The predominant role of bats in our local ecosystems is that of insect predator. A single little brown bat (Myotis lucifugis), which is native to the Florida Panhandle, can eat 1,200 insects (including mosquitoes) in one hour of feeding! In Texas, a recent study put the economic value of bats due to their consumption of agricultural pests on cotton farms at $74/acre. Extrapolated values of bats’ pest suppression services to US agriculture is in the billions of dollars annually.

Other species in warmer climates eat fruit and play a major role in reforesting rain forests in Central and South America—after digesting the fruit they leave seeds in their droppings (guano is excellent fertilizer, by the way), helping replant 95% of the very trees they feed upon. Some species feed on nectar, filling the same role as bees and helping pollinate bananas, avocados, cashews, and figs.

Contrary to popular belief, bats are not blind and many have excellent vision. However, they do rely heavily on echolocation to sense prey and are extremely accurate hunters. Viewed close up, many people consider the small, furry animals rather cute, as opposed to frightening. They often fly erratically because they are chasing very small flying insects, so the only reason one would end up in a person’s hair is if a mosquito flew through it with a bat in chase! While vampire bats do exist, there are only 3 out of over 1,000 species of bats that feed on blood, and they all live in Latin America. They also tend to feed on the blood of livestock.

Building a bat house is a great activity to do with kids interested in wildlife. Photo credit: Carrie Stevenson, UF IFAS Extension

Building a bat house is a great activity for kids interested in wildlife. Photo credit: Carrie Stevenson, UF IFAS Extension

Human contact with bats is rare unless the bats are sick, which is why one found on the ground should be left alone. Rabies transmission from bats accounts for only one death per year in the United States—a statistic much less than that of deaths from dog bites, bee stings, and lighting strikes! In fact, several towns in Texas with the highest populations of bats in the country have recorded zero human bat-transmitted rabies cases.

Bat populations are declining in North America due to disease (particularly white-nose syndrome), loss of habitat, and the slow reproductive cycle of bats. However, you can help the world’s only flying mammal by installing a bat house in your yard. Keep in mind that bats attracted to bat houses prefer to be in open areas away from trees (where their predators hide), and the house should be installed at least 12 feet in the air. Bat houses can be purchased or built rather simply—this UF IFAS Extension publication outlines several types, or visit Bat Conservation International’s website for simple instructions.

What can you do about a colony of bats in a building?

What can you do about a colony of bats in a building?

Bats are extremely beneficial, but they can be unwelcome guests when they choose to roost indoors, like this evening bat. Photo credit: LeiLani Davis.

Bats typically sleep during the day in natural structures such as trees and caves. In areas with few natural roost structures, bats may instead choose to spend their days in buildings.

 

Bats are beneficial because each bat consumes hundreds of insects per night. Bats save farmers billions of dollars annually by substantially reducing the abundance of insect pests. However, they can be unwelcome guests when they choose to live in buildings. The safe, humane, effective way to coax a colony of bats out of a building permanently is through a process called an ‘exclusion’.

 

A bat exclusion is a process used to prevent bats from returning to a building once they have exited. It is accomplished by installing a temporary one-way door. This one-way door can take many forms, but the most tried-and-true is simply a sheet of heavy plastic mesh screening (with small mesh size) attached at the top and along both sides of the sheet, but open on the bottom. The one-way door should be attached over each of the suspected entry/exit points bats are using to get in and out of the building.

 

It is illegal to harm or kill bats in Florida, but exclusions from buildings are allowed if you follow practices recommended by the Florida Fish and Wildlife Conservation Commission (FWC). According to Florida law, all bat exclusion devices must be left in place for a MINIMUM of 4 consecutive nights with temperatures above 50 o F before each entry point can be permanently sealed to prevent re-entry by bats. Also, it is unlawful in Florida to attempt to exclude bats from a building between April 15 and August 15, which is bat maternity season. This is when female bats form colonies and raise young that are unable to fly for their first few weeks of life. If bats were excluded during this time period, young bats (called pups) would die indoors.

 

For more information on how to conduct a bat exclusion, check out this video that features interviews with bat biologists from the University of Florida, FWC, and the Florida Bat Conservancy: How to Get Bats out of a Building.

 

For additional information on Florida’s bats, visit University of Florida’s bat advice or FWC’s bat website.

 

Remember, bat maternity season in Florida runs from April 15 to August 15. If you have a colony of bats roosting indoors that you want to exclude, you must either act quickly or else wait until the middle of August to coax them out.