Small Mammals and Bats

Small Mammals

Short-tailed Shrew, photo by John MacGregor

Short-tailed Shrew
Photo by John MacGregor

 

Twenty-seven small mammal species are known to occur in Kentucky. This number is based on a statewide small mammal survey conducted by KDFWR that began in 1988 to determine the distribution of all small mammals in KY. The survey utilized pitfall, bottle, and snap traps placed in a variety of habitats on public and private lands. This comprehensive survey produced over 9000 specimens and determined that the Northern Short-tailed shrew was the most widely distributed small mammal in the state. Species with extremely limited distributions included the Southern Short-tailed Shrew, Southern Red-backed Vole, Allegheny Woodrat, Marsh Rice Rat, Cotton Mouse, Hispid Cotton Rat, Masked Shrew, and the Long-tailed Shrew.  

Bats

Rafinesque's Big-Eared BatBats are the only true flying mammals. They belong to the mammalian order Chiroptera meaning ‘hand wing’ which references the elongated finger bones that make up a bat’s wing (see line drawing below.) All of Kentucky’s bat species are insectivores, meaning they all primarily eat insects. They respond to the lack of insect availability in the winter by hibernating (or heading south to warmer regions.) Bats that hibernate in Kentucky will mate in the fall and winter. Female bats store sperm over the winter and ovulation and fertization do not occur until the females arouse from hibernation. Females usually emerge from hibernation before males. In many species, they establish maternity colonies where they will have their young. A few species like the gray bat will gather in caves, others like the Indiana bat form colonies under loose tree bark, and still others may gather in manmade structures like the big brown bat. Additionally, some species such as the red bat will remain solitary. Each female may bear between one to four young called ‘pups’, generally from late May through June.

Sixteen species of bats have been documented in Kentucky (see list below.) Fourteen of these species are considered permanent or seasonal residents. The Seminole bat appears to be expanding its range into Kentucky and possibly breeds here now. The Brazilian (or Mexican) free-tailed bat occurs as an occasional wanderer, though there is prehistoric evidence that the species used to reside in Kentucky. Three of Kentucky’s bat species are federally endangered, the Virginia big eared bat (Corynorhinus townsendii virginianus), the Indiana bat (Myotis sodalis), and the gray bat (Myotis grisescens). The Northern long-eared bat (Myotis septentrionalis) is listed as federally threatened.

To learn more, click on any of the species links below. Photos and Kentucky distribution maps are provided for each species. Line drawings showing basic anatomy of a bat are also included below. They help highlight the key features used to identify certain species. Keep in mind that distinguishing among some of the Myotis species is hard even for a trained biologist!


Note:  A calcar is the cartilaginous spur that extends from the ankle. A keeled calcar refers to a calcar with a small flap of skin extending beyond it. The presence or absence of this characteristic helps biologists to identify some bats. Another thing biologists look at is the tragus, which is shaped differently among species. The tragus is a fleshy projection in front of the ear canal that helps a bat with sound localization. Bat biologists even look at the length and density of bat toe hairs to aid with identification. Talk about attention to detail!! Luckily, some bats can be identified without looking at any of these characters.


Bat illustration by Rick Hill
Illustration by Rick Hill, KDFWR after Schwartz

 
 

Common Myths about Bats

Are bats blind? Do they drink blood? Will they fly into my hair? Here’s some common myths and facts about bats:

Myth:  Bats are flying rodents.

Fact:  Bats are actually more closely related to primates than rodents.  They are generally long-lived and most only have one young per year.

Myth:  Bats are blind.

Fact:  Bats can see as well as most other mammals but most rely more on a sophisticated sonar system, echolocation, to get around and capture prey.

Myth:  Bats attack people and/or will get tangled in their hair. 

Fact:  A bat may swoop towards you in pursuit of prey but echolocation allows them to be very accurate flyers and avoid obstacles, including your hair. 

Myth:  All bats drink blood.

Fact:  Only vampire bats feed on blood. Of the 1300+ bat species found worldwide, just three species are vampire bats. They are found only in Mexico, Central America and South America.

Myth:  All bats carry rabies.

Fact:  Like other mammals, bats can contract rabies but less than one half of one percent do.

Myth:  Bats are dirty animals

Fact:  Like cats, bats are constantly grooming themselves to keep clean.

Bat Behavior

Gray bats leaving their roost

Gray bats leaving their roost

Sometimes bats seem to fly erratically around humans but they are just in the pursuit of prey. Most humans are near outdoor lights of some kind at night. Lights attract insects and insects attract bats. Bats have a swooping motion when they feed and they can dive at insects close to you under lights at night. They use a sophisticated navigation system, echolocation, to get around so they are not going to get caught in your hair like the old wives’ tale suggests. Echolocation is like sonar where the bats produce high frequency sounds that bounce off objects creating echoes that return to the bat. The echoes allow the bat to tell the size, speed and direction of movement for objects around them. With echolocation, bats can detect something as fine as human hair in total darkness!

During the spring months, most species of bats will be transitioning from their wintering sites to their summer sites to establish maternity and bachelor colonies. The pregnant females will usually go to the same area where they were born to have their young. Sometimes these areas can be man-made structures such houses, attics, barns, or garages. These bats will also roost under window shutters and behind gutters, any place that provides privacy, protection, and warmth for them so they can raise their young.

The summer months (late May to July) are when baby bats, called pups, are being born. This is a time of year when you may start to see bats on the ground or in your house. Not all baby bats survive, unfortunately. Mid to late July is typically when they learn to fly, or become volant. They are like teenagers first learning to drive. They often end up in your house or garage as they can take wrong turns testing out their wings. The best thing to do is to keep all pets and children away from them as they typically will take off again when they have rested. However, if you see what appears to be an apparent injury, please refer to the list of wildlife rehabilitators.

During the fall months, the opposite occurs. Bats will be leaving their summer areas to migrate back to their wintering areas, which can be caves or warmer climates just like birds. During this time, bats can become confused and tired and will find a place to rest, sometimes in our houses, garages, or even on the sides of buildings. The best thing to do is to leave them alone and keep children and pets away. 

Q&A for Kentucky Homeowners

This information is primarily for people who are having a problem with bats in their home or other structure and want help on how to deal with them. If you observe several bats during the summer, more than likely you have what is known as a maternity or nursery colony, a group of females that congregate to have and raise their young. The species you will most likely encounter are big brown bats and little brown bats. Without intervention, they can come back to the same site year after year. Bats may be observed as early as April when they come out of hibernation but usually they are not noticed until May, when the maternity colonies begin forming. Sometimes people can live in harmony with bats year after year. However, it is undesirable to have bats flying in your living quarters (e.g., bedroom, den, etc.). Many homeowners become aware of bats in their home in June and July. It is during this time that juveniles are learning to fly and get around and may accidentally enter your living quarters.

I have discovered bats living in my attic, chimney, etc. What should I do?
The only way to successfully deal with a bat problem is to “bat proof” your house but first you need to properly exclude the bats. You may wish to hire a Nuisance Wildlife Control Operator to do this or you may choose to do it yourself. The first thing to be done is to find where the bats are entering/exiting and set up a “one-way” exit there at the proper time of year. You will also need to seal up all other possible entry points. There are many helpful resources available to you that explain how to do this. You may start by reading “Bats: Information for Kentucky Homeowners” by Thomas Barnes, UK Cooperative Extension Service. This document should answer most of your bat questions including how to exclude bats from your home. Bat Conservation International’s website also has info on bats in buildings and an excellent document (includes photos) describing in detail how to exclude bats from buildings. Penn State Cooperative Extension and Outreach offers one of the most comprehensive documents for homeowners on bats, A Homeowner’s Guide to Northeastern Bats and Bat Problems.

I found a bat flying in my house. What should I do?
If you have not had any direct contact with the bat, treat it as you would a bird and open doors and windows to the outside while blocking entry points to the rest of your home. Keep in mind that when a bat is in an enclosed space, such as a room in your house, it will circle repeatedly. If you are in the room with the bat, the circular flight seems menacing, but the bat is simply trying to escape the room. The bat may wear itself out and land on something, you may place something like a coffee can or a shoebox over it and then slide a piece of cardboard under the container.  You should never directly handle the bat.  Although a bat may fly in a window or open door now and then, you could possibly have a colony living somewhere in your house so refer to the above Q/A.

Can I just have someone from Fish and Wildlife come out and take care of the problem for me?
Kentucky Department of Fish and Wildlife Resources only offers guidance on how homeowners can deal with bats. However, we maintain a list of permitted nuisance wildlife control operators that a landowner can hire to assist in dealing with and excluding nuisance wildlife. Some deal specifically with bats.

I called a nuisance wildlife control operator and they said they couldn’t help me until August 15! What am I supposed to do in the mean time?
Operators cannot adequately deal with bat maternity colonies until after the recommended date of August 15 due to the fact that there could be flightless young present (from mid-May to mid-August.) Adult bats exit every night and return to nurse their young. If exclusion methods were fully implemented, flightless young could become trapped inside your house and starve to death causing an unsanitary and unnecessary problem. HOWEVER, if you are having bats flying in your LIVING QUARTERS, the nuisance control operators can determine how the bats are moving from say your attic to your living area and exclude them from doing so. They can also close some of the bat’s alternative exits, as long as they leave the main exit open until August.

Why can’t I just kill the bats?
All bats in Kentucky are protected by state law. There are no legal toxicants for bat control. The best method of control is “bat proofing” your home so that more bats will not use it in the future. See the first Q&A.

Do bats pose a human health concern?
[Bat Conservation International (BCI) has a good general overview in their “Answers to questions about bats and public health document.]
Rabies:  Any mammal can contract rabies; however, the incidence of rabies in bats is low, < 1%. Be advised, however, that if you find a bat crawling on the sidewalk during the middle of the day, it is “out of its element” and is most likely sick. If someone has handled such a bat, they should contact their local health department and have the bat tested for rabies as a precautionary measure. Exposure to rabies virus requires contact between the infected animal’s saliva or nervous tissue with mucous membranes (e.g., your eyes, nose, or mouth) or an open wound or scratch. The Centers for Disease Control and Prevention (CDC) advises that if a bat is found in a room with a sleeping individual, an unattended child, or a person with a disability and exposure is uncertain, the bat should be tested. Visit the CDC’s website for more information on bats and rabies.
Histoplasmosis: This respiratory illness is caused by a fungus naturally found in the soil in warm and humid areas. It is known for its association with bird roosts because the droppings enhance the growth of the fungus. Bat droppings or guano can facilitate the growth of the fungus too, but fortunately, the fungus does not normally survive in the hot, dry attics where homeowners may find a bat colony. However, precautions should be taken to avoid potential exposure – see cleaning up bat droppings below. Human exposure to the fungus happens when dry fecal matter is stirred up and fungal spores are dispersed and inhaled by humans. Visit the CDC’s website for more information on histoplasmosis.
West Nile Virus: Bats can contract West Nile Virus; however, since this virus can only be spread by the bite of an infected mosquito, there is no threat to humans from an infected bat. 
Parasites: Bat ectoparasites are usually host specific, meaning that they cannot survive without the bats. They pose no threat to humans or their pets.

What should I do about their droppings (guano)?
If the guano is located where there is no human activity, the best thing to do may be to leave it alone. Fresh and scattered guano can be cleaned up by simply using your broom or hose, but removal of large accumulations of guano requires that precautions be taken. To protect yourself from being exposed to fungal spores, the guano should be sprayed with a bleach mixture (9 parts water to 1 part bleach) to minimize dust and you should use a respirator over your nose and mouth. Simply shovel the guano into plastic bags and double bag before removing. If you have significant accumulation of guano (> 2 in high) may want to contact your local health department and/or hire a professional company that specializes in the removal of hazardous waste. [Before starting a job or activity where there’s a possibility of being exposed to Histoplasma, you may wish to consult the document Histoplasmosis: Protecting Workers at Risk.

Can I put a bat house up for my colony?
Yes, but occupation success varies based on many factors. It is recommended that you erect a bat house as early as one season before you evict your colony so that the bats can begin investigating the alternate site. The colony may choose to occupy the bat house after they have been properly excluded from your home. BCI is a great source of information on bat houses including plans, installation, tips for success, etc. Be sure to look at their Criteria for Successful Bat Houses.

 

Bat Diseases

White Nose Syndrome (WNS)

White-nose syndrome (WNS) is a devastating disease found in North America that is caused by a “cold-loving” fungus. This white fungus grows on hairless skin tissue like the bat’s muzzle, hence the name “white-nose”. It has caused unprecedented mortality in some of our hibernating bat species, especially in the northeastern U.S where it was first discovered. April 2011 is when the disease was first documented in Kentucky. It is now found in caves across the state and is believed to be responsible for significant local population declines for some species such as little brown bats. For more detailed information, decontamination procedures, map showing the spread of the disease, etc. go to http://whitenosesyndrome.org.

 

Rabies and Histoplasmosis

For information on rabies and histoplasmosis, see "Do bats pose a human health concern?"

Injured or Sick Bats

If you have found an injured or sick bat, please ensure no children, pets or other animals can come into contact with it. Due to WNS, we are tracking reports of bats through our Report a Bat form.

If the bat is on the ground and does not appear to be injured, you can cover it with a small box (shoebox size) and use a flat piece of cardboard to slip between the ground and the bat. Once the bat is secure in the box, you can then find a tree to place the bat on without handling it. If the bat is still there after 24 hours, please use the Report a Bat Form.

Bats as Pets

In many cases, a bat removed from the wild does not live long. Not only is the practice detrimental to the bat, holding bats in captivity is against the law. Unless the bat is obtained from a legal source and a Captive Wildlife Permit is obtained in advance, 301 KAR 2:081 prohibits holding native bats as a pet.  

Collecting Permits

The Scientific and Educational Collecting Permit authorizes the collecting and holding, even temporarily, of wildlife for zoological, educational or scientific purposes.  Go to the Scientific and Educational Collecting page for more information and to download the application.