

In the case of bats for me I think I feel the pulses of bats because it’s quite powerful, more than hear it. It’s probably undertone resonance or something.
I haven’t heard any for a while and my hearing is deteriorating but bat numbers collapsed and I haven’t seen them either.




I use it all the time for the variable brightness flashlight and screen-as-light-source. Also sun and moon info, asteroid alerts.
And there’s a bunch of stuff that’s potentially very useful. Making a live map from a map image sounds very interesting, e.g. with a historical map.