Bats, the only flying mammals, inhabit diverse environments across Ohio, playing an important role in the ecosystem by consuming large quantities of insects. Their presence extends throughout the state, often remaining undetected due to their nocturnal habits. Understanding their habitats helps appreciate their ecological role and coexistence with humans.
Common Bat Species in Ohio
Ohio is home to a variety of bat species, each with distinct characteristics and habitat preferences. The Little Brown Bat (Myotis lucifugus) and Big Brown Bat (Eptesicus fuscus) are among the most frequently encountered species in the state. Little Brown Bats are relatively small with a reddish-brown to dark-brown coat and a wingspan of about 10 inches. Big Brown Bats are slightly larger, reaching a wingspan of 12-13 inches, and possess a reddish-brown to dark-brown fur with a somewhat puffy nose.
Other species found in Ohio include the Eastern Red Bat (Lasiurus borealis), known for its bright red color and solitary, tree-dwelling nature. The Hoary Bat (Lasiurus cinereus) is Ohio’s largest bat, identified by dark fur with white tips and a wingspan nearing 17 inches. The Tri-colored Bat (Perimyotis subflavus), formerly known as the Eastern Pipistrelle, is one of the smallest bat species in the United States. The federally endangered Indiana Bat (Myotis sodalis) is also present, often found in wooded areas near streams during summer.
Natural Roosting and Hibernation Sites
Ohio’s bats utilize various natural structures for both roosting and winter hibernation. Caves and abandoned mines serve as hibernation sites, known as hibernacula, where bats spend the colder months from late October to early April. These underground locations provide stable temperatures, ranging from 45 to 50 degrees Fahrenheit, which allows bats to maintain torpor and conserve energy during periods of insect scarcity. Some caves in Ohio can house thousands of hibernating bats.
During warmer months, bats commonly roost in trees throughout Ohio’s forests. They seek shelter in tree hollows, under loose or peeling bark of dead trees, and within dense forest canopies. Species like the Eastern Red Bat and Hoary Bat are primarily tree-roosting bats, often found alone among the leaves. Indiana Bats frequently roost under the loose bark of dead or dying trees and in tree hollows, particularly those near water sources.
Human-Made Structures as Habitats
Beyond natural environments, bats utilize human-made structures for roosting and shelter. Attics are a common choice, providing warm, dark spaces that mimic natural cavities. Big Brown Bats and Little Brown Bats are known for forming large colonies in attics, especially during the maternity season. These bats can enter buildings through very small openings.
Barns, abandoned buildings, and bridges provide habitats for Ohio’s bats. These structures offer protection from predators and the elements and suitable conditions for raising young. Some bat species may roost in hollow trees and abandoned buildings throughout the year. Bat houses are increasingly used to provide safe roosting sites, with some capable of housing hundreds or even thousands of bats.
Seasonal Shifts in Bat Residency
Bat residency in Ohio changes throughout the year, driven by seasonal needs for reproduction and survival. During the spring and summer, female bats establish maternity colonies, often in warm, sheltered locations such as attics, barns, or hollow trees. Pups are typically born in May and June and remain dependent on their mothers for several weeks; maternity colonies disperse as young become independent by mid-July.
As temperatures drop and insect populations decline in the fall, Ohio’s bats either migrate to warmer regions or seek out hibernation sites. Migratory species, including the Hoary Bat and Eastern Red Bat, travel south for the winter. Other species, such as the Little Brown Bat and Big Brown Bat, remain in Ohio and enter a state of hibernation in caves, abandoned mines, or even within the walls and attics of buildings. These winter roosts, or hibernacula, ensure their survival until spring.