Bats were a group of wild, flying animals of generally small size that fed on other small mammals, insects, reptiles, or fruit. Although the majority of bats were small, a few larger varieties existed. Bats were almost all nocturnal.
Just rats with wings if you ask me...
— Purfbin Doogrick
Description
Most bats were roughly the size of a small bird although larger bats existed. All bats were adept at perceiving their surroundings in the dark though the precise mechanics differed by species, with most bats using a form of blindsight involving sound —or darkvision in the case of shadowhunter bats.