I have noticed multiple people asking about the requirements for monster spawners to spawn their respective mob, and haven't been able to find any posts about it, so I have decided to create my own one. Firstly I'll start off with the overall requirements.
Overall requirements:
- All mobs spawn in an area that is 9x9, centered on the spawner (4 blocks horizontally from each side)
- All mobs spawn in in a volume of 9x9x3, centered on the spawner (1 block vertically from the bottom and top face)
Non-hostile/peaceful mobs requirements:
- Farm animals, such as the Chicken, Cow, Sheep and Pig all require a grass-block to spawn on
- These mobs also require light to spawn (above light level 8)
Hostile mobs requirements:
- All hostile mobs (Skeleton, Creeper, Spider, Zombie, Enderman and Cave-spider) require only air to spawn on
- Those mobs ^ require light levels of 7 and below in order to begin spawning
- Nether mobs, such as Pigmen, Magma cubes, Ghasts and Blazes require air to spawn on, but spawn at any light level
Overall requirements:
- All mobs spawn in an area that is 9x9, centered on the spawner (4 blocks horizontally from each side)
- All mobs spawn in in a volume of 9x9x3, centered on the spawner (1 block vertically from the bottom and top face)
Non-hostile/peaceful mobs requirements:
- Farm animals, such as the Chicken, Cow, Sheep and Pig all require a grass-block to spawn on
- These mobs also require light to spawn (above light level 8)
Hostile mobs requirements:
- All hostile mobs (Skeleton, Creeper, Spider, Zombie, Enderman and Cave-spider) require only air to spawn on
- Those mobs ^ require light levels of 7 and below in order to begin spawning
- Nether mobs, such as Pigmen, Magma cubes, Ghasts and Blazes require air to spawn on, but spawn at any light level
Other mobs:
- Iron golems require air to spawn on/in
- Squids require water and to be below y=46 to spawn
- Villagers require air to spawn on/in
- Ocelots require jungle leaves to spawn on
- Slimes require a slime chunk to spawn in (will write up a tutorial on how to find your slime chunk)
- Slimes spawn below y=40 and at any light levels (when in the slime chunk)
Please message me or reply to this post if you want more specifics or you think I have missed out any key parts.
Thanks, ~3G
P.S: My IGN is PlayingOnMy3G and nickname is King3G. Be sure to ask me in-game if you require any help on any minecraft technical aspects (including redstone)