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Bats on the ceiling of a cave in New York.

Bats hibernating in a New York cave. Photo by New York Department of Environmental Conservation

Bat Facts Calendar



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A town in the Netherlands built a bridge for walkers and bikers – and for bats. Within the bridge, bats have 3 different areas: an enclosed area for cold winter months, crevices along the sides for roosting in spring, and room to hang beneath the bridge during summer.
Happy Groundhog’s Day! What do groundhogs and bats have in common? Like bats, groundhogs hibernate to survive the winter. They share many characteristics because both are mammals, like us.  In coming days look for facts on common characteristics of mammals. 
Mammals share common traits. Only mammals have true hair.  Other traits are not as obvious.  For example the lower jaw in mammals is a single bone.  This is unique; all other vertebrates have more than one bone making up the lower jaw.

All mammals have a four-chambered heart and a diaphragm, a sheet of tissue that separates the heart and lungs from the rest of the internal organs.
Mammals give birth to live young (except for a few, like the duck-billed platypus) and produce milk to feed their young.  Usually only females produce milk, but the male Dayak fruit bat, found in Malaysia and Borneo, is an exception.
Unique to mammal brains is a region called the neocortex, which handles sensory perception and spatial reasoning. Generally, mammals have more complex brain functions than other animal groups. 
Mammals are endothermic, which means they keep their body temperature constant regardless of the temperature around them. During hibernation, bats become heterothermic, which means they lower their body temperature to save energy.

Mammals are classified into groups called Orders.  Many scientists recognize 19 different Orders of mammals (some recognize more).  Bats are in the Order Chiroptera, the second most diverse group of mammals. 
There are over 1,000 different species of bats, making up about one-fifth of all mammal species. Rodents are the most diverse order of mammals with over 2,000 species.
Know any young artists? Encourage them to participate in the national Endangered Species Day Youth Art contest. Artwork submitted can be any federally listed species, including the Indiana bat. The contest encourages young people to learn about endangered species and express their knowledge through artwork. Contest deadline is March 15, 2013.
Bat biologists are busy conducting surveys right now. They identify the species and count the number of bats hibernating in caves and mines. Getting into the caves, then identifying and counting bats can be difficult. Some bats are on ceilings 50 or more feet high and others are in very small spaces.
Places where bats hibernate are called hibernacula. Most hibernacula are caves and mines. The largest Indiana bat hibernaculum has over 170,000 Indiana bats.
How do you count 60,000 Indiana bats? Traditionally, large clusters of bats were counted by measuring the dimensions of the cluster and then multiplying by the density of the bats in the cluster, about 300 to 400 bats per square foot.
Happy Valentine’s Day.  Share some bat facts with your Valentine! Courtship behavior is complex in some bat species, but nearly nonexistent in others.
For modern bat surveys, we take digital photos of large bat clusters. Back in the office, we count bat noses in the photos to estimate the total cave population. Not only are we more accurate, but this reduces disturbance to bats because biologists spend less time in the hibernacula.
Other species of bats hibernate in caves with Indiana bats. Like Indiana bats, little brown bats typically hibernate in clusters, although not as tightly as Indiana bats. Other species, like the tri-colored bat, usually hibernate singly.
Caves used by gray bats are in limestone karst areas of the southeastern United States. Karst is a topography that occurs where soluble rock, like limestone, is at or near the surface. Water slowly percolates through fractures, dissolving the rock and creating sinkholes, caves, and other features.
Caves used by gray bats are in limestone karst areas of the southeastern United States. See a picture and learn more about gray bats.
Most Indiana bats hibernate in natural caves. Historically, the Indiana bat’s winter range was restricted to cavernous limestone areas in karst regions of the east-central United States, especially in Indiana, Kentucky and Missouri. See a map of cave distribution in the United States.
Ground water in karst areas is easily contaminated because surface water is rapidly channeled below-ground through sinkholes without the benefit of filtration or exposure to sunlight, which removes some contaminants.
Protecting karst environments protects water quality for people, as well as habitat for bats and other cave fauna. Living with Karst brochure.
Bat Cave in Carter Caves State Park is home to the largest Indiana bat population in Kentucky. About 35,000 Indiana bats were found in that cave during the last survey in 2011.
Cave River Valley in Indiana was purchased to conserve multiple caves used by bats, the scenic beauty of the valley and some rare natural habitats. Unfortunately, in January 2011 Endless cave was the first cave in Indiana documented with white-nose syndrome. Hopes for Indiana Bat Rise and Fall at Indiana’s Cave River Valley.
Indiana bats also hibernate in abandoned mines. About 30 mines have hibernating populations of Indiana bats. Some have been used as hibernacula by Indiana bats for a century or more.
Magazine Mine in Alexander County, Illinois, hosts hibernating bats and Unimin Corporation, the mine owner, is a valued partner in bat conservation. In 2017, Unimin donated Magazine Mine to the Organization for Bat Conservation.
In 2011, about 45,000 bats hibernated in Magazine Mine, which is remarkable considering that this underground silica mine was not abandoned until 1980. Endangered Indiana bats were first discovered there in 1996, about 100 bats at that time.
White-nose syndrome was verified in Illinois in 2013 and by the next winter and early spring thousands of bats had died in Illinois hibernacula from the disease.
Magazine Mine is suspected to be one of only two silica mines that may offer safe havens for bats suffering from White-nose Syndrome, due to its superior ventilation and dryness.
Last updated: February 1, 2018