Why are my bats dying?

I live in IN. Yesterday I went into the loft of the barn, where there are usually thirty or forty bats clustered in the corners of the roof. I saw none, though I did hear a few squeaks coming from bats I could not see. Then I looked at the ground.
I counted fifteen dead bats on the floor in two minutes. There were probably many more that I couldn’t see, because it was pretty dim. Could it be a disease, maybe white nose disease? Or a parasite? Many of them were small, hairless pups and older pups that had fur.


Have you taken photos and posted them to iNat? Only a small subset of iNat users are on the Forum, I bet you’re more likely to get this in front of expert eyes via iNat observations.


Yup. The bat observations are here.


You might also, without touching them, gather them all together for a photograph of all of them in one pic to document the number that have died.

And contact the mammalogist with Indiana DNR here: https://www.in.gov/dnr/fish-and-wildlife/wildlife-resources/wildlife-science-unit-staff/


Will do. Is there a specific reason you said “without touching them”? I mean, could it be a disease contagious to humans?

I agree, contact the local small mammal expert at DNR. If that doesn’t lead to anything, your local health department might be interested and can arrange testing of any specimens that aren’t too degraded for rabies or possibly for White-nosed Syndrome. Keep in mind that some mortality of bats happens during breeding season, including from high temperatures in maternity roosts that may exceed tolerance of young bats.


Incidentally, bats generally do not die from White-nosed Syndrome in summer – it’s usually a late winter/spring occurrence resulting from disease stress during hibernation. Your photos also don’t suggest that is the cause.


No bat alive or dead should be handled with bare hands. There is always a small but real chance of rabies. If you want to collect the dead bats for disposal or for testing, use a stick or small shovel to place the bat in a plastic bag that can be tightly sealed (such as a Ziploc bag). If you’re disposing of the carcasses, bag them and put in an outdoor trash receptacle. Keep carcasses away from household pets and any wild animals that might scavenge them, in addition to preventing contact with humans. These are usual precautions on the chance that rabies is cause of death.


worst case, it could be something like rabies. if you’re not certain that a given bat is dead, and you handle one that bites you, that would be a potentially serious medical event, requiring prompt immediate treatment and testing. (you might not even realize that you’ve been bitten.) just to be safe, i would always wear proper PPE if handling bats.

since you have many dead bats, if you’re sure they’re dead, and if you have trouble contacting your state DNR and/or local public health department vector control section, you could collect one in a plastic bag and freeze it to preserve the evidence.

if you really think it’s white nose, there might be another local entity to contact. check https://www.whitenosesyndrome.org/contact/local-bat-expert.

if it turns out the bat is a federally protected species, you may also want to contact your regional office of the US Fish & Wildlife Service: https://www.fws.gov/visit-us.


@antrozousamelia Is into bats.

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Somebody who specializes can comment better, but what I understand from here is that bats are often hosts to zoonotic pathogens that can easily transfer to humans:

Some information from US CDC about zoonotic diseases:

So it seems a little risky to interact with bats without PPE?


Has there been a heat wave or some kind of disturbance to the barn recently? If most of the carcasses are pups, it could be parental abandonment or dehydration… It could also be heavy metal or pesticide poisoning from wherever the bats have been eating or drinking. It could also be rabies. It’s really hard to say why bats die if there’s no obvious trauma.

Please make a report via their sick or dead wildlife report portal, if you haven’t already.


And as others have said, contacting their mammologist directly is a good idea bwestrich@dnr.IN.gov and tshier@dnr.IN.gov

I am part of the team that handles the dead bat reports for California, and if this were in my jurisdiction I’d probably ask you to collect a couple carcasses in plastic bags and place them in a freezer, and then contact the public health department to see if they want to test the bats for rabies. Someone from the IN DNR may also want to test the carcasses, I’m not sure what their protocol is.

As others have said, if you need to collect or move bat carcasses, use heavy gloves or a shovel to move the carcass to a bag. Being overly cautious is always the right move when it comes to potential zoonoses. Do not touch the carcasses with your bare hands.


I took a photo of the dead bats. There were 30 but I only collected 28 of them because one was smashed into the floor and one was entangled in some mesh, I don’t think it died from entanglement though.IMG_4230|690x460

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Oof, that’s really sad. I definitely suggest sticking a few in the freezer to prevent further decomp, since the DNR folks are probably taking the weekend off and won’t get back to you until Monday.

That is really sad; you’ve gotten a lot of excellent advice here. Def contact your state’s DNR. I know if someone noticed this, our nongame biologist with ALDCNR would want to know (bats are in their jurisdiction; doing cave bio we sometimes work together). That may be a search term that helps you - whoever the “non-game biologist” is if you get stuck about who to contact.

It looks like @antrozousamelia gave you actual links & email addresses for IN dnr, please please do that! They will want to know.


It has been really hot lately, heat seems like a good explanation.
I will ask my parents if I can contact the mammalogists. Will they want to come to my house to collect samples? I’ll freeze one of the bats (tho I don’t know what my mom would say if she discovered a dead bat in her freezer. ;) )
And I’ll be very careful when handling the bats! Thanks!

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Thanks all for the replies, I’ll see what I can do! Thx!


They would probably want to come by and pick up a carcass, or might ask you to ship it. Kind of depends on who they have in the area, most likely. Definitely ask your folks first! Please let your mom know that having a dead bat contained within several plastic bags in the freezer poses no health risks (I currently have ~150 in my own freezer!). If she’s not comfortable with that, you could maybe use a plastic cooler?

Since you’ve documented all the carcasses with photographs I’d recommend bagging all of them at this point, and putting them somewhere that other wildlife or outdoor pets can’t access.


SARS-CoV-2, for instance!


In North America the concern would be reversed, for us giving transferring SARS-CoV-2 to the bats… it’s a two way street. Obviously not a concern for these bats since they are already dead, but… my point is that we are also hosts of plenty of pathogens that can spill into wildlife populations.

We do not know (and will likely never know) if bats are the originator of SARS-CoV-2, and anti-bat rhetoric ironically makes zoonotic spillover more likely because it increases persecution.

Sorry, perhaps too far off topic.