B is for the Bats, Which are Dying by the Millions

9 thoughts on “B is for the Bats, Which are Dying by the Millions”

    1. Hi, Lisa; you are right that WNS is a major problem, and I appreciate you taking the time to write about it. However, as someone who spends a lot of time in caves, helps with bat research, and assists local fish and wildlife agencies in monitoring the bat populations, I feel like I need to comment and add some nuance, and correct a few pieces of misinformation.

      First, there is no evidence that humans exploring caves are a cause of the white-nose spread. The best research we have shows the fungus spreading bat-to-bat along migration routes, and not spreading outside of those routes the way we would expect if humans were transmitting it. Caves that have been closed for years, for example, still become infected, while well-visited caves with few bats may show no signs of the fungus.

      We have, in fact, no evidence that human transmission of the fungus has ever occurred. There was initial speculation that humans brought the fungus from Europe, but that was and remains speculation without any evidence. The picture is a little more complicated, too, since we’ve learned the fungus is endemic in Europe, but there is also an Asian strain. We probably will never know how it arrived, and the makes people want to fill in the answer by jumping to conclusions one way or another. Doing so is bad science, however human it may be.

      Even without the evidence for human transmission, though, those of us who work with bats and study caves use effective decontamination procedures for preventing any potential human spread, no matter how unlikely. These include removing all mud from gear after visiting a bat cave; cleaning hard gear with bleach, lysol, or 409 (which kill the fungal spores); and using hot-water soaks for soft gear (which also kills the fungus at the appropriate temperature). You are welcome to read more detailed protocols here: https://www.whitenosesyndrome.org/sites/default/files/resource/national_wns_decon_protocol_04.12.2016.pdf

      The trouble is that bats transmit the fungus effectively to one another, and so although we can eliminate any chance of transmitting the fungus ourselves, we can’t stop the spread by doing that, or even really affect it (since human transmission was never a major vector, if it was any vector at all). Bats can and do travel hundreds of miles between their hibernacula and their summer roosts, and so over the past decade we have seen the edge of infection move down the Eastern seaboard by about 100-150 miles every year as infected bats mix with uninfected populations.

      A second problem is that infected bats can be moved much farther by human systems; live bats have been found in containers on ships and trucks, and in cargo areas on airplanes. So the possibility exists that we, humans, will spread the disease–but likely not in a way that we can prevent by decontaminating or avoiding caves.

      There are a few things people can do, and your suggestion to put up bat houses is a good one. Especially in areas where there are few tree or rock roosts for bats during the summer, a bat house can give bats a safe place to stay.

      Another very good thing to know is what to do if you find bats in your house–do not attack them, grab them, or panic. Instead, simply open a window and close the doors to the room with the bat, and it will find its own way out.

      Finally, let me say that the absolute most important thing for people who are exploring caves as part of recreation or science is to stay out of caves with bats during the hibernation season for your area. In the northeast, that is typically Oct1-Apr30. Visiting bat caves in the summer does no harm, since the bats are not there–however, disturbing hibernating bats, especially those stressed by the fungus, can cause them to wake early from hibernation, burn up fat reserves, and die before making it through the winter. We’ve seen a bit of rebound in some bat populations our area lately, but we really need to take care of our bat caves to protect the individuals that remain.

      If you go in caves outside of the hibernation season, follow the decontamination protocols. The risk of human transmission is very small, but this is definitely a better safe than sorry case. Certainly do not take gear used in heavily infected areas to uninfected states or areas; use a separate set of gear for those.

      And remember, there are many, many caves that do not harbor bats. If you enter a cave during hibernation season for any reason and see bats, turn around and go somewhere else. Caves that get very cold (significantly below freezing), caves that flood several times a year, and caves that are very wet are generally not used by hibernating bats and are safe to visit year-round (provided you take steps to do so responsibly and safely for yourself). For guidance on safe and responsible caving practices, visit the National Speleological Society at caves.org.


      Liked by 1 person

      1. Oh my gosh, thank you so much for all of this. I did my best to research but many of the sources had not been updated in a while. More than one stated that humans were probably to blame for the invasion of the fungus from Asia or Europe to North America. So, thought it safe to include that information.

        Of course, I never meant that scientist or professionals should stay out of caves. If proper procedures are followed there is little to nothing to worry about but there are people who do not respect cave/mine closures or who do not follow proper decontamination procedures. They are who I am talking to here.

        Whether or not we are ultimately to blame the fact is we are not as careful or caring of our environment and the animals that share this planet with us as we should be. Bats have long been seen by the general public and ugly, disgusting, dangerous, and unworthy of our help. My goal was to change that with this post.

        Thank you for all the additional information you provided. When I get a free moment I will go back through and update any misinformation and link directly to your comment for further reading :)


        1. No problem, I’m always happy to see people I follow writing about WNS because we absolutely need to be more aware of it and understand it better. Respecting closed caves and mines, especially during hibernation, is a huge part of that. I just also want people to know they can explore safely with endangering bats as well. I always prefer to say “here’s how to do it well, and safely” and bring those people into the community who might otherwise go into a mine full of hibernating bats and not know better.


  1. Interesting points made here. I’ve heard some of this from other sources such as the presentation give before the bat flight from Carlsbad Caverns–an impressive sight if one is ever near that attraction.

    The dwindling bee population is another situation that could have very bad implications for all of us.

    Arlee Bird
    Tossing It Out


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