Bats are passive flying mobs that spawn in darkish regions underground.
Spawning
Bats can spawn in groups of 8 [JE only] / 2 [BE only] on translucent blocks below layer 63 in the Overworld, where they can spawn at light levels 3 or more down. You will also need at least two air blocks (or top hatches). or the upper plate of the block above the pin level). The Java version requires a light level of 6 or less to appear between October 20 and November 3. In a hyper-flat world, bats spawn under the top layer of no air, leaving through the usual restrictions of class 63. drip
Bats do not drop items or experience when killed.
Behavior
Bats are small, less than 1 block tall and wide. random ringing. They often fly aimlessly and tend to the east, sometimes diving into lava and causing fires.
Bats hang upside down on the undersides of solid blocks when hibernating, but cannot cling to transparent or non-solid blocks. When a player approaches an upside-down racket, the racket will fly away, even if the player cannot see it. This also happens when a player passes a block with a hanging racket.
Bats disappear when they are too far from the player.
The bat collision box does not interact with the player or redstone components.
Bats are one of the best Mobs that MC Wiki has just updated for Minecraft.