By Tammy O'Neil, Wildlife Care Manager

The big brown bat (Eptesicus fuscus) is one of the most common bats in Ohio. This bat is similar in appearance to other brown bats but it is Ohio’s largest brown bat. It is found throughout the state and is one of the species of bats that hibernate in winter. Big brown bats will add about 25 percent to their body weight in preparation for winter and hibernate from November to mid-March. While they are considered a cave dwelling bat, big browns are the only bat that will hibernate in buildings during the winter. They can be found in clusters, but those hibernating in buildings generally range from a few to just one. Most people do not even know they are in their houses or buildings because they remain well hidden and are very sedentary. Their heart rate drops to 40 to 80 beats per minute compared to the normal range of 250 to 450 beats per minute. They do not eat or defecate while in hibernation. They choose dwellings and locations that remain above freezing, preferring temperatures around 49 degrees.

Big browns may be seen flying around during warm spells in the winter. It is during these periods of activity when people usually find them in their homes or outside. Since these warm spells do not last long, many bats get into trouble when the temperature quickly drops again.

The Kevin P. Clinton Wildlife Center typically receives the most bats for rehabilitation during the fall and winter. Most of the bats are big brown bats and have been found in buildings or outside during colder temperatures. Those brought in after being removed from a home are usually very healthy, but some are treated for low weight and weakness. The weak and thin bats are given supportive care until they reach a healthy weight and can go into hibernation. All bats with a healthy weight and no injuries are put into artificial hibernation for the winter. This allows us to mimic natural conditions and prevents us from disturbing them as much, so stress levels are lower and we can take in more bats this way. We create an artificial hibernaculum, setting the temperature and humidity as close to those they prefer in the wild. We set up different spots for them to choose from, as each individual is picky and must have choices within its hibernaculum. Obviously, we can’t duplicate the exact natural environment for them, so we do weigh, feed and hydrate them every couple of weeks on days it is warmer outside. This allows us to perform a physical exam and make sure they are maintaining healthy weights. In 2018, the center had 18 bats housed over the winter in hibernation. 

The Kevin P. Clinton Wildlife Center is accepting animals by appointment ONLY, between the hours of 10 am and 4 pm. If you have an injured and/or orphaned animal, you must first call the Wildlife Hotline at 440-256-1404 x2131 to discuss your concerns and determine if an appointment is necessary. Only animals booked with an appointment can be accepted and cared for.

Please follow our new animal acceptance protocols:

1. You must call the Wildlife Hotline at 440-256-1404 x2131 to make an appointment to bring an animal to the center.
2. The animal must be in a secure container.
3. Arrive to appointment on time (do not come early). 
4. Be aware you will be asked to wait outside while the animal is being assessed.

For more information about bats, click here.