As the daylight hours begin to shorten, and we approach the official end of summer on September 21st, we aren’t the only ones thinking about cooler weather approaching.  Inside the bat cave here in Cave Springs, AR, the endangered Gray Bat begins to think about finding a better spot for the winter.

You may have caught a glimpse of the Gray Bat if you happened to be in Cave Springs at either dawn or dusk between March and September.  Dusk is when the bats leave the cave to feast on insects, returning to their cave at dawn to sleep.  Many local residents credit the gray bat with significantly reducing the amount of pests that we encounter in the area around Cave Springs.

Gray Bat, Adam Mann, Environmental Solutions and Innovations

Gray Bat (Myotis grisescens)

Photo: Adam Mann, Environmental Solutions and Innovations

The Watershed Sanctuary is home to thousands of endangered Gray bats (Myotis grisescens) and endangered cavefish (stay tuned for the upcoming blog on cavefish).   The Gray bat is the largest bat in the Myotis Genus but weighs only 7- 16 grams (a nickel weighs 5g, a toothbrush weighs 18.5 g).  The Gray bat was put on the endangered species list on April 28th, 1976.

Have you ever seen a Gray Bat?  Gray bats have two distinct identifying characteristics from other bats:

  1. A uniformed gray fur color on their back (other bat species are more multicolored)
  2. The wing membrane is attached from the tip of their wing to their ankle, instead of their toe, as in other species within the Myotis genus.

Gray Bat Foot, Adam Mann, Environmental Solutions and Innovations.

Foot of a gray bat

Photo: Adam Mann, Environmental Solutions and Innovations

Female Gray bats give birth to a single offspring each year, any disruption to that process can cause large numbers of bats to die and populations to decline, therefore making it difficult for Gray bat populations to rebuild to the numbers it would take to have them removed from the endangered and threatened species list.

If hibernating bats awaken from their torpor (temporary hibernation) too early in the winter, it can cause them to use up their stored energy reserves thereby increasing their chances of starvation. Human disturbance is often credited for these interruptions of torpor, resulting in a negative impact on the gray bat populations.

The threat to gray bats remains due to their vulnerability to human interaction and habitat loss.   In contrast to many bats, the Gray bats are strictly cave dwellers, living in caves, temporarily hibernating in caves, and rearing their young in caves.   Gray bats are geographically limited to limestone karst areas in the Southeastern U.S., these are areas with huge beds of soft limestone rock underground that crack and erode over time causing the formation of caves, the essential habitat for Gray bats.

Bat Cave, Lake at Cave Springs, AR

Bat Cave, Cave Springs, AR

Shrinking habitat and increased human impact in these cave ecosystems make it difficult for bat populations to survive and reproduce adequately.  If disturbed during hibernation, the Gray bats will be forced to use up their energy reserves that are crucial for their survival through the winter.  Any disruption of young bats in their first couple of months can prove catastrophic to their reproductive success.

The IRWP, in cooperation with the US Fish and Wildlife Service, the Arkansas Natural Heritage Commission, and the Arkansas Game and Fish Commission, is doing its part to preserve the population of Gray bats at the Partnership’s Watershed Sanctuary in Cave Springs.  This includes both habitat protection and public education.  Join us in our effort to spread the word about this rare species residing in the Illinois River Watershed!


Additional Resources:

Arkansas Game and Fish Commission

U.S. Fish and Wildlife Service

Missouri Department of Conservation

The Nature Conservancy


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