We have a large barn on our property that is home to what seems to be a healthy population of bats. Several people/groups rent space from us through the winter and into the spring to store their campers and trailers. We let the bats stay for free. Recently, one of our renters picked up their trailer, which had been stored for nearly a year with a tarp over it. When the tarp was removed, it was covered in guano, as expected. To our surprise, however, there was also an immature bat (known as a pup), most likely a Big Brown Bat (Eptesicus fuscus), on the tarp.
To give an idea of scale, in the photographs above and below, I am wearing a standard leather work glove. Big Brown Bats are common and widespread in North America, as they are known from southern Canada through the United States, with the exception of south Florida and southcentral Texas. Big Brown Bats often overwinter in buildings, though some will migrate and overwinter in caves. During the summer, they roost in buildings or hollow trees. An impressive fact about the species is that they can fly up to 40 mph.
Bats are very beneficial, as they feed on insects including wasps, ants, and beetles, some of which are serious crop pests. No need to worry about this little one. Pups often fall from the roosting location; those that can climb are often retrieved by their mothers. I took this bat back into the barn and climbed a short distance up a ladder before putting the bat near a vertical beam. It immediately began climbing up towards the rafters.
Special thanks to my coworker Jeremy Sheets for providing his opinion that this likely is a Big Brown Bat.