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Tricolored bat with symptoms of white-nose symptoms.

Tricolored bat with symptoms of white-nose symptoms. Photo by NPS

Bat Facts Calendar



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The largest Indiana bat hibernaculum in Ohio is an abandoned mine; the Lewisburg Limestone Mine in Preble County where Indiana bats were first discovered in 1994.  The Mine's Indiana bat population in 2011 was estimated at 9,500 and other species of bats also use this mine. 
The only Indiana bat hibernaculum in Michigan is in a man-made structure, Tippy Dam. This hydroelectric dam in Manistee County is home to over 20,000 hibernating bats, including a small population of about 20 Indiana bats.
Researchers have monitored bats hibernating in Tippy Dam (Michigan) for more than two decades.  In 2011, they found a banded Indiana bat – based on banding records it is at least 11 years old!  Find out more »
Indiana bats hibernate in dense clusters, up to 500 bats per square foot. One reason is energy conservation. Clustered bats conserve heat while hibernating and share heat during periodic arousals. Northern long-eared bats, however, hibernate in small clusters or alone.
Hibernating bats may seem to be doing nothing, but physiologically they are busy striking a precarious balance between maintaining metabolic processes so they can recover from hibernation (for example, not allowing cells to freeze) but slowing processes sufficiently to survive winter on their fat reserves.
On this date 109 years ago, March 7, 1904, the “type specimen” of the Indiana bat was collected at Wyandotte Cave in Indiana.  A type specimen is the original animal from which a description of a new species is made.  That is why the species was given the common name “Indiana” bat.
Indiana’s Wyandotte Cave supports the largest Indiana bat population but is now threatened by white-nose syndrome.  Several research projects at Wyandotte will help us understand the disease.  We hope these efforts will help us ensure that Wyandotte will continue to be a bastion of recovery for Indiana bats.

While an Indiana bat hibernates it does not eat, surviving on its fat reserves.  But can it survive all winter without water?  Researchers think the need for water may be a major reason that bats arouse during hibernation and may affect how often they arouse.
Indiana bats with access to water may drink when aroused during hibernation, but some must survive with little or no water.  For them, water conservation is very important.  Bats minimize water loss by hibernating in very humid caves; some caves approach 100% relative humidity.
In Wyandotte Cave in Indiana, bats lap water from a wet wall in the cave during periodic arousals from hibernation.

Clustering during hibernation may help bats conserve water as well as energy.  When bats are tightly clustered each individual has less skin exposed, reducing evaporative water loss.
Indiana bats do not necessarily stay in the same spot during hibernation.  During arousals they have to maintain a higher body temperature, so to save energy they may move to warmer locations within the cave. 
Bats sometimes shift to colder areas in caves so they can hibernate at a lower temperature.  While this saves energy, there is a limit to the lowest temperature at which bats can hibernate, and it is different for different species.  The limit for Indiana bats is about 37 F.

Most bats do not choose to hibernate at the lowest temperature possible because the cost may be too high.  While hibernating at a lower temperature may save energy, it comes with physiological costs.  See more about these tradeoffs »
Although hibernation allows bats to survive the winter without food, there are costs. One cost is a suppressed immune system. Research shows that immune function is compromised in hibernating bats compared to non-hibernating bats. See more »

Hibernating bats look like they are sleeping, but hibernation is actually nothing like sleep.  In fact, research has shown that hibernating mammals may become sleep deprived and that may trigger periodic arousals during hibernation.  They arouse from hibernation to sleep!
In recognition of St. Patrick’s Day, today’s bat fact focuses on Ireland.  There are nine species of bats found in Ireland.  Irish bats include several species from the genus Myotis – the same genus as the Indiana bat.  More on bats of Ireland »
The Mexican long-nosed bat spends the winter in Central Mexico where males and females gather to mate. All mating occurs in a single cave.
Want to read the National Wildlife Federation’s “Seven Reasons Bats are Just as Cool as Batman?”  Here’s one – “Even their poo is helpful.”  Read more »
Caves where bats hibernate tend to have a stable temperature and humidity compared to outside the cave or mine, but that doesn’t mean the cave environment never changes. Caves “breathe,” exchanging air with the outside.  

You may experience a cave breathing if you stand outside a cave entrance on a hot summer day and get relief from the heat as cool air flows out of the cave.  The opposite can happen on a very cold winter day.  Cave air is in constant motion as it adjusts to surface changes.
The amount of air exchanged between a cave and the outside depends on the number of outside openings and the relative height of the openings.  In winter, colder air may be pulled in through a low entrance, forcing warmer air out of a higher entrance, called “chimney effect” airflow.
Caves with the most Indiana bats are typically large, complex systems that allow air flow.  Also, the larger volume and greater complexity buffers or slows changes in temperature. These caves often have large rooms or vertical passages below the lowest entrance that trap cold air and store it throughout summer.
Indiana bats, like most bats in the U.S., are small and shy and active only at night.  Most people rarely observe bat behavior, so bats are not well understood.  This week will be dedicated to discussing bat myths and misconceptions.

Contrary to common myth, bats will not fly at your head and get tangled in your hair. Bats are not naturally aggressive animals and generally try to avoid contact with people. Read more at https://bit.ly/153M1ux
Some people think of bats as flying mice.  Old English for a bat was flittermouse or fluttermouse, meaning flying mouse (from the German word for bat which is fledermaus). While both bats and mice are mammals, bats are not rodents and are more closely related to primates.
The expression “like a bat out of hell” refers to something that is recklessly fast and out of control.  In truth, while their flight may appear erratic, bats are just highly maneuverable. Perfect miniature flying machines!  Watch an amazing video of a bat in flight.
The saying “blind as a bat” is not accurate.  Bats can see, but they use echolocation (emitting a sound and receiving the echo) to maneuver in total darkness.  They depend mostly on echolocation to guide flight and locate prey.

A common myth is that bats will suck your blood.  Three species of vampire bats are sanguivores,  which means that they live by eating blood, but they do not live in the U.S.  They are found in Mexico, Central America and South America.  Find out more about these fascinating creatures.
Some people think that bats are dirty and carry diseases.  Actually, bats spend a lot of time grooming and cleaning themselves.  Colonial bats also groom each other.  Grooming helps them to stay clean and to control parasites.
Like all mammals, bats can carry rabies.  While most bats do not, there is no way to tell if a bat has rabies just by looking at it.  Rabies can be confirmed only by having the animal tested in a laboratory.  So be safe and never handle a bat.  See more information on bats and rabies.  
Last updated: February 5, 2018