“Bats are passive mobs that spawn naturally in caverns or other large enclosed spaces. Bats are the only passive mob able to fly, and the only flying mob that naturally spawns in the Overworld. They will often emit a squeaking noise, but do not do many other things that can affect gameplay. They do not drop any items or XP when killed, making them the least “significant” mob in the game. They can be used to find caves while mining underground because of their squeaking.”
Bats spawn in dark places (mostly caves).
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