A big brown bat navigates a course of hula hoops. Photo by Brown University.

Hi everyone! I hope you all had a good week! I found an interesting article about helping bats that are hibernating in caves.

Torpor, a state of lowered body temperature and much slower metabolism, is very important for cave hibernating bats. This torpor is often interrupted by people who are happy to explore underground, which can cause bats to burn off of precious stored fat. In order to lessen the amount of human caused disturbances in caves, many caves have been closed off to the public during known hibernation times. Sometimes by closing off the cave to the public, the bats inside are assured a good rest.

The blockades at some cave entrances have been equipped with corrugated metal pipes for the bats to use as exits. Sadly, according to recent observations by a biologist, the caves with corrugated pipes have been deterring bats instead of attracting them. According to the biologists’ study, the corrugated pipes create an acoustic effect that interferes with echolocation, which prevents bats from being able to fly properly. The effect was tested by having bats fly through two different custom-built flight rooms, one with a narrow corridor with dangling plastic chains to simulate vegetation and another tunnel with plastic hula hoops that simulated the raised rings on the corrugated pipes. In the study, bats had a 99% success rate in the first test with the hanging plastic chains and a 49% success rate when they flew through the tunnel with the hula hoops. The study also included readings of the test bats’ echolocation calls during the course. The timing and patterns of a bat’s echolocation calls change when they perform more difficult tasks, such as flying through the simulated corrugated pipes. The study showed that the raised rings on the pipes were creating navigational difficulties for the bats. This is most likely due to their echolocation calls bouncing off of the rings in a confusing way. One way to help solve the problem is by adding concrete to the inside of the pipes to smooth out the ridges and hopefully cause less disturbing feedback for the bats. However, that potential solution will have to be tested further before being implemented in caves.

If you want to read more about this study you can find the article outlining it here and here.

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