Why bats go to the bathroom or poop on the wall?
Bats defecate on the wall near the entry point and many websites are quick to point that out but no-one has ever answered the question of WHY. Why do bats do that? I have a theory.
I believe that they do it inadvertently. As a bat begins his descent back into his hibernacula (roost-site) he must slow down on arrival. Some species of bats can reach speeds over 100 mph in horizontal flight and they have been observed going faster than most cars on the interstate!
Since bats must slow down, they must do a reverse thrust prior to landing that compresses their pelvis and literally forces them to go to the bathroom leaving that black poop on the wall. The brown dirty spot at the entry point is due to sebum which is basically just bat funk, and we all have sebum. With all of that flying around at high speeds I guess the bat gets sweaty and dirty and just gets funky so that accounts for the dirty brown spot at the entry point but not the bat guano.
In regards to the poop on the wall, what I am talking about is the small droppings that are almost always located stuck to the wall like a little lizard or small mouse droppings. Lizard droppings on the wall often look like little cigars with a white cap or end to it. Bat guano also by itself usually has no odor and crushes easily. If you look closely you will see little-undigested insect parts in it as well.
So keep in mind that this is MY theory, but until science produces anything contrary I firmly believe it.
That is the interesting thing about this industry, while there are many things on this earth that have been studied to no end – wildlife is still in need of researchers and study.
Here is a picture of a bat entry point which shows the dirty spot related to the secretion of Sebum.
Below is a picture of bat guano stuck to the wall and as I said, my theory says it occurs due to the pelvis compression that occurs during the reverse thrust on attempted and successful landings of the bats during entry into the roost.
So as you can see, bats can be quite messy. Bats are one of the animals that little study has been done on them in comparison to other animals, although one particular species has been studied quite a bit. The Mexican free-tailed bat has been studied a lot and they are indeed the bats responsible for the evidence I have in this article. I know this because I took these pictures and actually saw the bats that were roosting here in both locations. The top picture is from a job where I actually monitored the activity of the bats leaving as well through the use of a product called trap-alert and bat cones. The Bat Cone is a professional bat removal product that we use a lot. I modified the cone to include a sensor that would send me an email when a bat triggered the exit path door. That job produced thousands of emails as the bats exited the columns. Here are a few images of how I did that.
This is a video I made of my first attempt at using this setup. I actually had removed these bats from a building earlier that day. They were stuck in a vertical wall in a building, I cut the wall and rescued these bats from their certain death and then used this setup to test my idea and release the bats back into the great Louisiana night!