How can anyone in Illinois think that bats are scary?
Despite what you see in the movies, these fascinating flying mammals wouldn’t hurt a fly! Well, technically, they would hurt a fly, or a mosquito, or a moth. But other than that, bats are harmless. 🙂
Did you know there are 14 kinds of bats in Illinois?
It’s hard to believe the diversity and amount of species that can be found in Illinois! But, unfortunately, when you see a bat, it’s typically pretty difficult to determine which kind of bat it is. These nocturnal creatures fly incredibly fast and are only active at night.
#1. Big Brown Bat
- Eptesicus fuscus
- Larger-sized bat with around a 12-inch wingspan.
- Brown fur with black ears, wings, and feet. Wings are hairless.
Big Brown Bats are widespread all over Illinois.
If you look, you’ll find these bats inside caves, tunnels, or other human structures.
Big Brown Bat Range Map
This nocturnal bat primarily eats insects, especially ones that fly at night. However, their preference is to eat beetles.
The Cucumber Beetle is their favorite, which benefits farmers because these insects are terrible pests for agriculture. Many farmers in Illinois even use bat boxes to attract Big Brown Bats to their property!
Though rabies is common in all bats, research has shown the disease is rarer in this species.
The reason for this fact is that many Big Brown Bats have immunity to rabies. Interestingly, researchers discovered that these rabies antibodies get passed down from generation to generation!
#2. Hoary Bat
- Lasiurus cinereus
- Brown hair with grayish-white tips. Wings and belly are brown and hairless, with a wingspan approximately 15.5 inches.
- Males are almost double the size of females.
You’ll typically find Hoary Bats roosting on trees in woodland forests. But occasionally, they will go into caves to stay with other bats.
Hoary Bat Range Map
This species prefers to hunt for prey while flying over wide-open areas or lakes. Hoary Bats hunt alone and enjoy eating moths. They’re known to travel up to 24 miles in a single night to gather food!
Though the Hoary Bat is not endangered, it does suffer a loss in numbers because of wind turbines. Hoarys’ migrate each year back and forth from North America to Central America, and it’s thought that they confuse the wind turbine with being a tree as they seek a place to rest. As you can imagine, these bats meet a horrible death.
#3. Silver-haired Bat
- Lasionycteris noctivagans
- Medium-sized bat, flathead, and the upper part of the tail are covered in thick fur.
- Mostly black all over with white tips on hairs, with a wingspan that is approximately 11.5 inches.
The Silver-haired Bat is known to fly more slowly than other bats in Illinois.
Look for Silver-haired Bats in forests inside tree cavities or bark crevices. They’ve also been known to seek shelter in outbuildings.
Silver-haired Bat Range Map
Silver-haired Bats hunt for soft-bodied insects, such as moths. Interestingly, they also eat a lot of spiders. They accomplish this feat by foraging low to the ground to find food, unlike many other bats.
Unfortunately, rabies occurs more often in this species when compared to other bats.
#4. Little Brown Bat
- Myotis lucifugus
- Glossy brown fur on the body. Wings are hairless and black with a wingspan that is approximately 9 to 11 inches.
- Despite its name, it has no connection to the Big Brown Bat.
The Little Brown Bat is common and lives throughout Illinois.
Look for them in sheltered places such as human structures, woodpiles, tree hollows, and occasionally caves.
Little Brown Bat Range Map
Little Brown Bats will commonly use a bat house for roosting. Many people put up bat houses to attract them to their property to control pests like mosquitos or insects that harm crops.
Little Brown Bats only have a few natural predators, like owls or raccoons. Unfortunately, most of their mortality is caused by parasites or White-nose syndrome.
White-nose Syndrome is a fungal disease that grows around the bats’ mouths, ears, and wings. This illness is spread during hibernation and is responsible for the loss of over one million Little Brown Bats between 2006 and 2011. As of 2018, the Little Brown Bat is an endangered species.
#5. Eastern Red Bat
- Lasiurus borealis
- Medium-sized tree bat with thick, long fur. Ears are short and round. Wings are long, pointed, and have a wingspan of approximately 13 inches.
- Males have distinctive rusty red-colored fur, and females have more of a soft shade of red.
- Both have white patches of fur on their shoulder.
Eastern Red Bats like to roost in trees in Illinois.
I love their red fur, which I think makes them look cute!
Eastern Red Bat Range Map
These bats are relatively fast flyers with good maneuverability. They are insectivorous, which means they prey primarily on different insects, with their favorite being moths.
Unlike most bats that only produce one offspring, Eastern Red Bats have three pups in a litter.
Eastern Red Bats have few predators. However, sometimes hawks, aggressive Blue Jays, and crows will attack them. This bat is also killed by flying into cars or wind turbines. Unfortunately, this species has the second-highest mortality rate from wind turbines.
#6. Tricolored Bat
- Perimyotis subflavus
- Small bat with blond hair on the chest. Their wingspan is approximately 8 to 10 inches.
- The “tricolor” name comes from the coloration of the three distinct bands of hairs on their back: dark gray on the bottom, yellowish-brown in the middle, and brown or reddish-brown on top.
- Formerly known as the Eastern Pipistrelle.
The Tricolored Bat is the smallest in Illinois!
Despite their small stature, Tricolored Bats can live to be 15 years old, which is a long time for bats! And interestingly, Tricolored Bats mate in the fall, but the female stores the sperm and doesn’t become pregnant until spring.
Tricolored Bat Range Map
Did you know the Tricolored Bat’s natural predators include many birds of prey, snakes, skunks, other bats, and Northern Leopard Frogs? It’s crazy to think of a frog eating a bat, but it shows how tiny these mammals are!
Related Article: The 14 Types of Frogs in Illinois!
Tricolored Bats used to be considered one of the most common bats around. But, unfortunately, their numbers have been decimated by White-nose Syndrome. It’s thought that 70% of their population has succumbed to this fungal disease.
#7. Northern Long-eared Bat
- Myotis septentrionalis
- Fur and wing membranes are tan, with black ears and black wings: long tail and a wingspan up to 10 inches.
- Look for their long pointed ears.
- Also called the Northern Myotis.
Northern Long-eared Bats are found in Illinois in forested habitats with spruce and pine trees. They typically roost in trees during the summer and switch to a new roost every other day. In the fall, these bats migrate to caves to hibernate together with other species of bats.
Northern Long-eared Bat Range Map
Northern Long-eared Bats have incredibly accurate echolocation calls, which helps them navigate their dense forest environments.
Unlike most bats, Northern Long-eared Bats capture their prey by plucking them from a surface rather than catching them while in flight. They eat insects, with moths being their favorite.
Sadly, the Northern Long-eared Bat has been threatened by White-nose Syndrome, a fungal disease that kills many bats. This disease has decreased their population by 99%. Click play to learn more below!
#8. Evening Bat
- Nycticeius humeralis
- Smaller bat with a prominent dog-like jaw.
- The majority are dark brown with black muzzle, ears, legs, and wings, but some are a lighter brown. Their wingspan is approximately 10.5 inches.
The Evening Bat doesn’t enter or even hibernate in caves, which is good news because that helps them avoid White-nose syndrome, a terrible disease that has killed millions of bats over the years.
But the bad news is:
They have a shorter life span than other bats in Illinois.
Evening Bat Range Map
Most only live for 4 years, but some are lucky enough to make it to 6 years.
Look for Evening Bats roosting in structures, including tree cavities, under bark, in Spanish moss, and buildings. They eat a wide variety of insects, including beetles, moths, winged ants, and flies.
#9. Eastern Small-footed Bat
- Myotis leibii
- Small bat with a short flat head and a dark black face that resembles a dark mask.
- Black ears, wings, and feet. Shiny brown dense fur, pointy ears, and sloped forehead. Their wingspan is approximately 8 to 10 inches.
The Eastern Small-footed Bat is one of the smallest bats in Illinois.
Eastern Small-footed Bats get their name from their abnormally small hind feet, which you can see in the photo above.
Eastern Small-footed Bat Range Map
This species, like most bats, feeds on flying insects such as moths, beetles, and flies. But the Eastern Small-footed is capable of filling their stomachs within an hour of eating. So these bats prefer fast food to fine dining. 🙂
The Eastern Small-footed Bat has more extended thumbs and claws at the top of its wings than other bats. This adaptation helps them immensely because they spend much of their time climbing in rocky areas.
This species has several threats, including White-nose syndrome, water pollution, and human disturbance during hibernation. Even small amounts of noise and light are enough to wake bats. When a bat wakes up during hibernation, it expends energy and depletes its fat reserves to survive winter. So sadly, if a bat is repeatedly disturbed, it will likely die and not live until spring.
#10. Indiana Bat
- Myotis sodalist
- The fur can be black or dark brown, and the belly can be light gray to reddish-brown. Their wingspan is approximately 9 to 11 inches.
- The best way to tell them apart from other brown bats is their pink lips.
The Indiana Bat is highly endangered in Illinois.
Its population has decreased by more than 50% over the past 10 years. But, unfortunately, they can quickly spread White-nose Syndrome to each other because they hibernate in such large groups.
Indiana Bat Range Map
These bats live in a variety of habitats all over Illinois. First, they’re found primarily in hardwood forests in giant trees. Then in winter, many of these species get together in different caves and hibernate in large masses.
#11. Mexican Free-tailed Bat
- Tadarida brasiliensis
- Smaller bat with gray fur on front and back, face, ears, wings, and legs are light black.
- Ears are short and rounded with lines inside and ruffled on the bottom.
- Wings are elongated and narrow with pointed tips. Their wingspan is approximately 12 to 14 inches.
The Mexican Free-tailed Bat is the fastest in Illinois!
Their long narrow wings help make them quick and have direct flight patterns while catching their flying prey. They also use echolocation to help to navigate in the night sky.
Mexican Free-tailed Bat Range Map
This species primarily roosts in caves, but they can be found in any structure with an opening and dark hiding place.
Mexican Free-tailed Bats have glands in their skin that cover their body. These glands leave a scent that other bats can smell, so they know that this roost is only for the Mexican Free-tailed Bats.
#12. Rafinesque’s Big-eared Bat
- Corynorhinus rafinesquii
- The fur is gray on the back and white on the belly. Face and ears are pinkish browns.
- Wings are dark brown, and ears are very long, measuring over an inch (hence their name).
- Wingspan is approximately 10 to 12 inches.
The Rafinesque’s Big-eared Bat lives in a variety of places. They prefer mature forests but will also go into abandoned buildings or under bridges.
Rafinesque’s Big-eared Bat Range Map
This nocturnal bat is insectivorous and feeds on mosquitoes, beetles, and flies. Their diet consists of over 90% moths, which are located using echolocation.
Luckily, the White-nose Syndrome fungus, which kills many species of bats, doesn’t affect the Rafinesque’s Big-eared Bat.
#13. Southeastern Myotis
- Myotis austroriparius
- The fur varies from bright orange-brown to gray. The wingspan is approximately 9 to 11 inches.
- Females are often more brightly colored than males.
Southeastern Myotis prefer to live in bottomland hardwood forests in Illinois.
Look for them near water, as this is where they like to roost and search for food. The diet of the Southeastern Myotis consists mainly of caddisflies.
Southeastern Myotis Range Map
The Southeastern Myotis are a crucial food source for the Barred Owl during nesting season. Interesting, when it’s not the nesting season, the owls tend to leave the bats alone.
This species is unique compared to other bats in Illinois because females primarily have twins. Most other bats only have one offspring.
#14. Gray Bat
- Myotis grisescens
- Smaller bat with long thumbs and claws. The fur is dark gray.
- Black wing, ears, and legs. The wingspan is approximately 9 to 11 inches. Ears are medium in length.
Out of all the bats in Illinois, the Gray Bat is most dependent on caves.
Therefore, do not look for these bats in tree cavities, barns, artificial structures, or anywhere else!
Gray Bat Range Map
Gray Bats prefer to forage over water, such as streams, to consume night-flying insects. They typically feed in small groups, as long as there is enough food for everyone. But if food becomes scarce, they want to be alone and become very territorial.
Unfortunately, the Gray Bat is on the endangered species list because of its population decline due to human disturbance. Pollution, urbanization, deforestation, and mining are all to blame.
Do you need additional help identifying bats in Illinois?
If so, this field guide should be able to help you.
Which of these bats have you seen before in Illinois?
Leave a comment below!