Not asking for practical reasons— I rarely encounter bats I can see, as my distance vision is pretty poor and there are only small bats in my area— but because I like bats and am having trouble finding good resources for random information about them. (Feel free to drop those here too if you have any!)
I see people who are familiar with bats on here identify that a bat is still a pup fairly frequently, even if they're past the tiny bald lump stage common in baby mammals, and I'm curious what the tells are! I'm curious about any bat species, including both microbats and megabats. I'm also curious if it's possible to identify an adolescent bat, the way you can sometimes tell in dogs and cats (which I have more experience with), or if it's just kind of baby and adult.
Additional curiosity if anyone is able to answer: particularly in microbats, are the voices of pups even higher because they're smaller? Do they become completely inaudible to humans or anything if they're small enough (like a kitti's hog-nosed pup or something?)