Rats,
Of all the familiars I have shared my life with, more than a few were Rats.
Surprisingly intelligent, And very socially oriented, They listened better than some dogs I've known.
But they did like to steal and hide jewelry... Little Kleptos.
Never had the luck you've had with bats, though.
If you like bats you might like this...
https://www.youtube.com/watch?featur...&v=Kk5oHQa1Ars