Mob spawning

A naturally spawned creeper and chicken.

Mob spawning is how both passive and hostile mobs are created.

Mob spawning on chunk generation

This feature is exclusive to Java Edition.
 

Animals

In Java Edition many animals generate upon initial chunk creation. These spawns occur only once per chunk. They are not affected by the /gamerule doMobSpawning command.

One in ten newly-generated chunks attempts to generate animal mobs, usually in packs of up to 4 of the same species. The spawn attempt always starts on top of the highest available block in a randomly chosen column within the chunk. The chosen position must not be a solid block for the animals to generate. Once the starting position is chosen for a chunk, a second position is chosen in a 9×9 block area around the starting position. Blocks toward the center of the 9×9 area are more likely to be chosen than blocks toward the edge. The block does not need to be a grass block nor does it need to be illuminated as it does with mob spawning. If an animal can spawn at the second position, it does so. The second position becomes the first position, and a new second position is chosen like before in a 9×9 area. This process can repeat until each chunk has attempted to spawn 1–4 mobs.

In Bedrock Edition animals do not spawn during chunk generation, but they continually attempt to spawn everywhere as part of the environmental spawning algorithm, according to their spawn weights, biome tags, and block requirements (see Bedrock Edition under Spawn Cycle, below).

There are 2 types of animals: common animals and biome-specific animals.

Common animals

Common animal mobs do not spawn in desert, badlands, beach, snowy plains, river, ocean, or mushroom fields biomes.

Mobs Weight Group size
Sheep 6 4
Chicken 5 4
Pig 5 4
Cow 4 4

Biome-specific animals

Some animal mobs spawn only in specific biomes. They can have several varying requirements, which are often times unique to that mob, such as specific light levels or spawn-able surfaces.​

Mobs Biome Weight
10 (in all savanna biomes)

6 (in all badlands biomes)

4
1
75
7
1
10
8
1‌

10‌

3
20
4 in plains

1 in savanna

8 (in savanna biomes)

5 (in windswept mountain biomes)

8
30
10 in regular jungle

40 in bamboo jungle

40
1 (5 in frozen oceans)
25
4 (20 in flower forests)
26 in oceans

16 in rivers

8
20
75
8
8 in taigas

5 in forests and windswept hills

Randomness for animal spawning is derived from the world seed, which means that worlds with the same seed always generate chunks with the same animals in the same places.

Monsters

Monsters cannot spawn when the difficulty is set to Peaceful (except for piglins and hoglins). At any higher setting they spawn when block light level is 0 and there is also an adequate level of sky light.

Common monsters

Common monster mobs can spawn in almost any biome in the Overworld (except for mushroom fields or deep dark). They can spawn on the surface and underground. The weight determines the spawn rate in the Bedrock Codebase.

Mobs Weight Group size
Zombie 100 2-4
Creeper 100 Individually
Skeleton 80 1-2
Spider 100 Individually
Enderman 10 1-2
Witch 5 Individually
Zombie Villager 5 Individually
Biome-specific monsters

Some monsters spawn only in specific biomes.

Mobs Biome

Other mobs

In Java Edition these mobs still spawn if the /gamerule doMobSpawning command is set to false, because they spawn as part of structure generation. In Bedrock Edition nothing spawns if the /gamerule doMobSpawning command is set to false.

Passive and neutral mobs
Mob Structure generation
Allays can spawn up to in 1-3 groups in a pillager outpost and a woodland mansion.
A single black cat spawns within or around a swamp hut upon generation.
Generate as part of the village generation.

Specific animals spawn as part of specific village structures: Animal pens (cow, sheep, pig, or horse), stables (horse, cow, or pig), butcher's houses (pig, cow, or sheep), and shepherd's houses (sheep).

Spawn from pillager outposts.

Generate as part of the village generation.

Generate as part of the village generation.

Each villager spawns in a house with a bed.

Hostile mobs
Mob Structure generation
Generate as part of some underwater ruins.‌
Generate as part of an ocean monument.
Created in the End when the dimension is created. The ender dragon can also be respawned by placing end crystals on the exit portal.
Generate as part of a woodland mansion.
Spawn from pillager outposts.
Generate as part of end cities.
A single witch spawns within a swamp hut upon generation.
Generate as a part of an igloo if it generates with a basement.

Can spawn as part of abandoned village generation, where they never despawn naturally.

Spawn cycle

Java Edition

Mobs are broadly divided into seven categories: hostile, passive, water creature (squids and dolphins), underground water creature (glow squids), axolotls, water ambient (all 4 types of fish), and ambient (bat). Most mobs have a spawning cycle once every game tick (1⁄20 of a second), but passive mobs have only one spawning cycle every 400 game ticks (20 seconds). Because of this, where conditions permit, hostile mobs spawn frequently, but passive mobs (animals) spawn rarely. Most animals spawn within chunks when they are generated.

Mobs spawn naturally within chunks that have a player horizontally within 128 blocks of the chunk center, and can only spawn within a 128 block radius sphere centered on the player. When there are multiple players, mobs can spawn within the given distance of any of them. Hostile mobs (and some others) that move farther than 128 blocks from the nearest player despawn instantly.

Java Edition mob cap

There are two caps, a global cap and a per-player cap. Note the spawn density mechanism may also be considered a "cap" of sorts, but takes effect later in the spawning process.

The mob caps are checked once for each spawn-eligible chunk. Spawn for the chunk may take the total number of mobs over the cap.

The caps for each mob category are as follows:

Mob category Cap
Monster 70
Creature 10
Ambient (bats) 15
Axolotls 5
Underground water creature (glow squids) 5
Water creature (squids, dolphins) 5
Water ambient (fishes) 20
Misc -1

The "misc" category is used only by entities that are not mobs, do not spawn naturally, and/or following different spawning rules than other mobs. As such the mob cap has no bearing on mobs of this category. The global mob cap affects only environmental mob spawning, and does not affect mobs spawned through breeding, spawn eggs, the /summon command, monster spawners, or any other type of mob spawning.

Global mob cap

All non-persistent loaded mobs are counted against the global cap, including those in chunks not in range of a player or eligible for spawns. The cap is scaled by the total number of chunks within a 17×17 chunk square around any player. The cap is then scaled as globalCap = mobCap × chunks ÷ 289. Because chunks that are in the range of multiple players are counted once, more chunks and higher mob caps result from the players spreading out.

Per-player mob cap

Each non-persistent mob in a chunk that has its center within 128 blocks horizontally of a player is counted toward that player's per-player mob cap. For each chunk, spawns are only allowed if at least one player has that chunk in range and has not reached their per-player mob cap.

Pack spawning

Example of a mob pack spawning. The mob spawning area is shaded blue. The yellow figures represent the actual positions that mobs could spawn in after checking the environment. Note that the mobs can spawn inside torch and ladder blocks. But they can't spawn on top of glass because it is not opaque. The red cube is the center of the pack.
Requirements for the spawning location of individual mobs.

For each spawning cycle, attempts are made to spawn packs of mobs per each eligible chunk. An eligible chunk is determined by the same check for which chunks are random ticked. A random location in the chunk is chosen to be the center point of the pack. The X and Z coordinates are chosen completely at random, while the Y coordinate is a random coordinate between the block above the highest block in the column and -64. This makes lower maximum elevations a strong way to increase spawn rates and is the reason why perimeters are so effective. If the block in which a pack spawn occurs is an opaque full cube, further pack spawn attempts are canceled. There are a maximum of 3 pack spawn attempts per mob category.

Before the attempt to spawn each mob in the pack, the position is offset by ±5 (triangular distribution) on the X and Z axes. Thus, while the pack can be spread out up to 40 blocks from the initial position for a pack size of 4, it's much more likely they'll be closer to the center. Approximately 85% of spawns are within 5 blocks of the pack center, and 99% within 10 blocks of the center. Mobs spawn with the lowest part of their body inside this area.

All mobs within a pack are the same species. The species for the entire pack is chosen randomly, but based on a weight system from those eligible to spawn at the location of the first spawn attempt in the pack. For later mob spawn attempts in the pack, if the selected species cannot spawn at the location (e.g. due to being in a different biome or structure) then that attempt fails.

The game checks on each spawn if the number of mobs that have been spawned for the pack is equal to the max spawn attempts, as well as the location's spawn potential.

Pack spawn size

Pack spawn attempts max out at:

  • 8 wolves, cod, and tropical fish
  • 6 horses and donkeys
  • 4 for any other mob

When the max pack size is less than the number of possible spawn attempts, some spawns attempts fail, but are seen more commonly in practice. Based on the number of mobs that have been successfully spawned. If the max pack size is greater than the number of spawn attempts, one gets only the number of spawns from the spawn attempts. Some mobs have a minimum and max pack size, meaning there is an even chance for any number of spawn attempts between them occurring.

Pack spawn location

For all dimensions, structure-based spawns take priority over biome for hostile spawns. This means that in a swamp hut, pillager outpost, Nether fortress (outer bounding box only when there is Nether bricks below it‌), and ocean monument, one sees only the corresponding hostile mobs for that structure within that structure.

In the Overworld, this depends on the location:

In the Nether:

Spawn conditions

Whether a spawn condition fails differs from the above determination if the game tries to spawn them in that biome. For example, dolphins can have pack spawns that occur inside of frozen ocean and deep frozen ocean biomes, but no other biomes. These rules apply to variants of the same mob, such as baby zombies and jockeys.

Each individual spawn attempt succeeds only if all of the following conditions are met:

  • There must be no players or the world spawn point within a 24 radius block distance (spherical) of the spawning block.
  • The number of loaded mobs of that type must be less than the mob cap for that type (I.e. the corresponding mob cap must not be full).
  • The mob's collision box upon spawning must not collide with another collision box. A mob cannot spawn inside of anything that would collide with it upon spawning.
  • The mob's collision box must not intersect with a solid block.
  • For all mob types excluding passives and fish, spawns fail unless within a 128 radius block sphere around the player. For fish, spawns fail unless within a 64 block radius of the player.[2]
  • /gamerule doMobSpawning is true.
  • For non-aquatic mobs, the spawning block and the block above that cannot be rails, powered rails, detector rails, activator rails, redstone power components, wither roses (except for wither skeletons) or sweet berry bushes (except for foxes).
Hostile mobs
  • The difficulty must not be Peaceful.
    • Piglins and hoglins can spawn in Peaceful.
    • Ocelots cannot spawn in Peaceful due to a bug‌[3].
  • For all hostiles other than guardians, drowned, and phantoms:
    • the block directly below it must have a solid, opaque, top surface (this includes top slabs, upside-down stairs, and others) or be soul sand, mud or a slime block.
      • Reversely, transparent blocks do not allow mobs to spawn on it, this includes any type of trapdoor or glass.
    • the opaque block directly below it must not be bedrock, barrier, or a command block.
    • The mob's collision box must not collide with any liquid.
    • The block above the spawning block must either be transparent or air.[note 1]
    • The mob must be immune to the damaging effects of the spawning block and the block directly below it. For instance, if the block directly below the spawning block is a magma block, the mob must be immune to fire damage. If the spawning block contains a wither rose, the mob must be immune to wither damage (currently, this is only true for wither skeletons).

Regarding a light level, the basic rules for spawning are as follows (compare it with Light § Mobs):

  • In the Overworld, block light level must be 0 and sky light must be 7 or below (which always occurs inside a cave).
  • In the Nether, block light level must be 11 or less. Sky light is always 0 in the Nether.
  • In the End, block light level must be 0. Sky light is always 0 in the End.

When doing the light check in the Overworld and End, the spawn chances are randomized and a spawn only occurs if the light level is less than or equal to a random number between 0 and 7. In the Nether, as long as the light level is below 11, the spawn is allowed.

Some mobs have some additional rules in addition to the ones above.

Mob Rules
Blaze
  • Spawns only in nether fortresses.
Drowned
  • Spawning block and block below must be water.
  • In rivers, has 1⁄15 chance to spawn.
  • In oceans, has 1⁄40 chance to spawn and must be 5 block below sea level.
Ghast
  • 95% chance of spawn failure.
Guardian
  • The spawning block and the block below must be water, including waterlogged blocks and bubble columns.
  • 95% chance of failure if the spawning block has sky exposure (details).
Hoglin
  • Cannot spawn on nether wart block.
Husk
  • The location of the spawn must have sky access.
Magma Cube
  • Cannot spawn on liquid.
Ocelot
  • Spawn has a 1⁄3 chance of failure.
  • Can spawn on leaves.
Piglin
  • Cannot spawn on nether wart block.
Skeleton (nether fortress)
Slime (swamp biome)
  • the spawning block must be in a swamp biome.
  • the spawning block be on level 51 through 69 inclusive.
  • chance of failure based on the phase of the moon.
  • 50% chance of failure.
Slime (slime chunks)
  • the spawning block is below level 40.
  • 90% chance of failure.
Stray
  • The location of the spawn must have sky access.
Wither Skeleton
  • Spawns only in nether fortresses.
Zombified Piglin
  • Cannot spawn on nether wart block.
Passive mobs
  • The mob's collision box must not collide with any liquid.
  • The light level of the spawning block must be 9 or brighter.
  • The block directly below the spawning block must be one associated to the mob, as per the table below :
Mob Spawning Blocks
Mooshroom

Mycelium

Turtle

Sand

  • the spawning block[4] must be y-level 66 or lower.
Parrot

Grass Block
Leaves
Logs
Air

Rabbit

Grass Block
Sand
Snow Block
Snow[5]

Wolf

Grass Block
Podzol
Coarse Dirt
Snow Block
Snow[5]

Fox

Grass Block
Podzol
Coarse Dirt
Snow Block
Snow[5]

Polar Bear

Grass Block
Ice

Goat

Stone
Gravel
Packed Ice
Snow Block
Snow[5]

Armadillo

Grass Block
Coarse Dirt
Terracotta
Red Sand

Frog

Grass Block
Mud
Mangrove Roots
Muddy Mangrove Roots

Camel

Sand

any other passive mob in this category

Grass Block

  • Striders ignore the precedent requirements. Strider spawning attempts with lava above check upward as long as there is still lava for if they can successfully spawn in a lava block with air on top.
Aquatic mobs
  • The spawning block must be water.

The mobs have some additional rules in addition to the one above.

Mob Rules

Cod
Salmon
Pufferfish
Tropical Fish
Squid
Dolphin

  • the block directly below the spawning block must be water.
  • the block directly above the spawning block must be water and cannot be waterlogged.
  • the spawning block must be between level 50 and 63, inclusive. This does not apply to tropical fish spawning in lush caves.
Glow Squid
  • the light level must be 0.
  • the spawning block must be level 30 or lower.
Axolotl
  • the block directly above the spawning block must not be a solid block.
  • the block directly below the spawning block must be clay.
Ambient mobs
  • The mob's collision box must not collide with any liquid.

The bat is currently the only mob in this category, which has some additional rules in addition to the one above.

Mob Rules
Bat
  • the block directly below the spawning block must be stone, granite, diorite, andesite, tuff, or deepslate.
  • the block directly below it must not be bedrock, barrier, or any type of trapdoor or glass.
  • If the real-time day is between October 20 and November 3, then the light level must be 7 or darker. Otherwise, the light level must be 4 or darker.
Spawn costs
Locations that do not have spawning potential reliant spawns are marked by wart blocks or netherrack.

The warped forest and soul sand valley biomes introduced a new mechanic to limit the amount of mobs that naturally spawn in them. The spawn cost (also called spawn potential or spawn density) takes on a value for each block in the biome. Certain mobs increase that value by some number ("charge") divided by their distance to the block. If a new spawn attempt would bring the "potential" of the spawning block above a certain threshold, the spawn attempt is canceled. This results in mobs not spawning too close to one another in these biomes, and new spawns in the area are completely blocked long before the full mobcap of 70 hostile mobs is ever reached.

More specifically, a mob may be spawned at a location if sum( existing mob's charge ÷ distance to mob ) × new mob's charge < new mob's maximum potential. While the code allows for different mobs to have different charges and maximum potential, all checked mobs have the same charge and maximum potential within both the warped forest and the soul sand valley.

Which mobs contribute to the charge, how much they add, and what the maximum potential is are all biome-specific. Mobs carry charge according to their current biome, and affect spawning in an adjacent biome even if they would not contribute a charge if in that biome. For example, striders in a soul sand valley affect enderman spawns in an adjacent warped forest, even though striders in the warped forest itself do not.

Due to the limited total number of mobs in soul sand valleys and warped forests, a larger-than-usual amount of mobs spawn in any space outside of these biomes, including in nether fortresses.

Notes
  • Buildings surrounded by air spawn more mobs inside than underground rooms because packs that spawn outside of the building can spawn mobs inside it. The mob caps tend to be reached in seconds.
  • If the player's view distance or the server view distance in multiplayer is at 9 or below, mob spawning is severely reduced (or they despawn too quickly), and may result in the player encountering no mobs at all. Set the view distance to 10 or higher to ensure mobs spawn correctly.

Bedrock Edition

Environmental spawning in Bedrock Edition shares broad similarities to natural spawning in Java Edition: Mobs spawn in a radius around the player subject to block conditions, lighting conditions, biome conditions, naturally generated structure conditions, and caps. Many mobs spawn in groups (called "packs" in Java and "herds" in Bedrock). One notable difference from Java Edition is that most animals can spawn at light level 7 or higher rather than 9 or higher.

There are two types of environmental spawns: cluster spawns and structure spawns. Structure spawns reproduce specific types of mobs at specific locations within certain naturally generated structures, such as nether fortresses, swamp huts, etc. Cluster spawns account for all other types of environmental spawns, including mobs that spawn individually (i.e. not in a herd of 2 or more). Both types of environmental spawns follow the same rules for spawn conditions and mob caps, except that structure spawns can exceed the monster population cap by 1 (see below).

Mob spawning in Bedrock Edition happens within a spherical shell 24-44 blocks away from the player on simulation distance 4. It happens in a quasi-spherical shell 24-128 blocks away from the player, restricted by a simulation distance and/or to roughly 96 blocks horizontally, on simulation distances 6 and higher. This means that mobs can spawn directly above or below the player (for example, phantoms in the sky or zombies underground). Mobs can only spawn in chunks that are being ticked. There is a 11⁄2000 chance of the mob spawning algorithm attempting to run per chunk, per tick.

Bedrock Edition mob cap

There are three mob caps that affect environmental spawning: a global mob cap, population control caps for general mob types, and density caps for specific mob types. The global mob cap is set at 200 regardless of difficulty. The global mob cap affects only environmental mob spawning, and does not affect mobs spawned through breeding, spawn eggs, the /summon command, monster spawners, or any other type of mob spawning. Chickens created by thrown or dispensed eggs are counted in the global mob cap. Only mobs that have spawn rules count toward the global cap (i.e. armor stands and minecarts do not take up cap space). In addition, mobs that are within ticking areas (both those around players and those set manually using the /tickingarea command) count toward the global mob cap; mobs not ticked do not count toward the global mob cap.

The population control caps limit how many mobs of each type and category can spawn within a 9 chunk by 9 chunk square region surrounding the chunk in which the spawn attempt is made. Mobs in chunks outside a ticking area still count toward population control counts as long as they were previously loaded (i.e. within simulation distance at some time) after relogging. The population control caps are split up into two distinct categories: a cap for surface mobs, and a cap for cave mobs. Cave mobs do not count toward the surface mob cap, and surface mobs do not count toward the cave mob cap. Whether a mob counts as a surface mob or a cave mob is determined by where or how it spawned, not where it happens to be at the moment. For cluster spawns, those that spawn on the highest spawnable block at a given coordinate count toward the surface cap, and any that spawn below the highest solid or non-solid but spawnable (e.g. ice or upper slab with air above) block count toward the cave cap. Structure-spawned mobs and converted mobs (i.e. drowned converted from zombies, witches from villagers, zombified piglins from pigs, and medium and small slimes from killed larger slimes) always count toward the cave cap, and monster-spawner-spawned mobs always count toward the surface cap.

There are five categories of mobs: ambient, animal, monster, pillager, and water_animal. The population control cap for each category and location of mob in each dimension is as follows (* denotes values that are coded in the game but not actually used by any mobs):

Population control caps
Category Location Overworld Nether The End
Ambient Surface 0 0 0
Cave 2 0 2*
Animal Surface 4 0 4*
Cave 0 4 0
Monster Surface 8 0 10
Cave 16 16 8*
Pillager Surface 8 0 8*
Cave 8 0 8*
Water_Animal Surface 36 0 36*
Cave 0 0 0

Some specific mobs types also have their own density caps. The density caps limit the number of those mobs to some amount below the applicable population control cap. Density caps are checked in the same manner as the population control caps. Caps are below (n/a indicates that the mob does not spawn in that environment at all).

Mob density caps
Mob Surface cap Cave cap
Cod 20 n/a
Creeper 5 unlimited (population control cap still applies)
Dolphin 5 n/a
Drowned 5 in ocean

2 in river

n/a
Ghast n/a 2
Phantom 5 n/a
Pufferfish 3 n/a
Salmon 10 in ocean

4 in river

n/a
Squid 4 in ocean

2 in river

n/a
Tropical Fish 20 for preset pattern

20 for random pattern

n/a

Bedrock spawn conditions

See also: Simulation Distance

The following rules apply to most mobs:

  • Mobs spawn at a distance from the player that depends on the world's simulation distance:
    • Simulation distance 4: between 24 and 44 blocks spherical radius from the player.
    • Simulation distance 6 and up: between 24 and 128 blocks spherical radius from the player, but limited horizontally by simulation distance and coding that restricts the spawning algorithm from running in chunks whose center exceeds 96 blocks from the player.[6]
  • The bottom part of the mob (i.e. the feet of a standing mob) can spawn only in an air block, or for water mobs in a water block. A few naturally-generated, non-motion-blocking blocks such as grass and flowers are ignored for this rule. If the mob spawns in a flower the block above the flower must be air.
  • The bounding box of the mob must not intersect any solid blocks. Mobs can spawn intersecting leaves, glass, and other transparent blocks.
  • There must be a block with a full, solid top surface under the spawn location for the mob to spawn on. (I.e. mobs cannot spawn on carpets, lower slabs, fences, right-side-up stairs, redstone repeaters, chests, etc.)
  • Mobs cannot spawn on transparent full blocks like glass and leaves.
  • For mobs that can spawn floating in water or flying in air, the block that is checked for spawning is the water or air block immediately above the first solid top surface block below the spot where the mob would spawn. (So for example, phantoms cannot spawn over a field covered in carpet, and fish cannot spawn in an ocean where bottom slabs cover the ocean floor.)
  • Most Overworld monsters cannot spawn if the sky light level is greater than or equal to 7 or the block light level is greater than 0.
  • Most Overworld animals cannot spawn if the (combined) light level is less than 7.

Cluster spawning

Cluster spawning happens in two stages: first attempt to spawn surface mobs, then attempt to spawn cave mobs. Before spawning, the population control cap is calculated based on the 9 chunks × 9 chunks square area surrounding the current chunk. Spawning begins by picking a random X and Z location within the chunk currently being evaluated. The Y coordinate is determined by starting at the world height and searching downward for a solid-top-surface block with a non-spawn-blocking block above it. The first such block that is found is considered to be the surface, and the algorithm attempts to spawn a surface mob herd. However, if the algorithm finds a solid block before finding a spawnable solid-top-block (e.g. if it finds a tree trunk directly under leaves), it does not make any surface spawn attempt. The algorithm then continues to search downward for the next suitable block with a non-spawn-blocking block above it. When a block meeting the criteria is found, the algorithm attempts to spawn a cave mob herd at that block location. Cave spawn attempts continue until the Y coordinate reaches the world bottom, and do not stop even if a cave herd was spawned.

Surface and cave cluster spawn attempts then go through the following steps to figure out what mob to spawn and how many:

  1. Picks a random mob.
    • If the current spawn location is in a liquid, pick a random water mob.
    • If the light level is 7 or higher, there are no other blocks above the current location, and the current location is a grass block, pick a random animal mob.
    • Otherwise, spawn a monster mob.
  2. Picks a random number of mobs to spawn in the herd. Each mob can have its own min and max herd size, and the herd size can depend on difficulty and biome.
  3. Make sure the spawn location has suitable spawn conditions.
  4. Limit the number of mobs spawning based on the global mob cap. No mobs spawn if the mob count already meets or exceeds the mob cap.
  5. For each mob to spawn, check that spawning it would not exceed the population control cap or mob density cap.
    • If spawning the mob would not exceed the population control or mob density caps, then the probability of a mob spawning can be calculated using the formula: (mob density cap - current mob density count) / mob density cap
  6. Finally, attempt to spawn the mob in the world.
    • Spawning the mob can fail; for example, if spawning it would cause it to spawn inside of a block or part of a wall.

Structure spawning

Structure spawn attempts occur at specific relative X and Z coordinates in naturally generated structures, known as "hard-coded spawn spots". The structures that have hard-coded spawn spots include swamp huts, ocean monuments, pillager outposts, and nether fortresses. Whenever a successful cluster spawn attempt occurs within a chunk that contains a hard-coded spawn spot, the environmental spawning algorithm also attempts a structure spawn. (Note that a "successful attempt" here means that a spawnable block was found, even if the spawn was then blocked by light level check or mob cap check.) The structure spawn attempt follows the same rules and steps described above for cluster spawning, with the following changes:

  • Instead of starting at world height and searching down to bedrock at the specific X and Z location, the search begins and ends at a specific Y values determined by the type of structure. Structure spawn attempts occur only on the first spawnable block found (i.e. the highest spawnable block) within that range.
  • The mob picked depends on the structure: swamp huts spawn witches, ocean monuments spawn guardians, pillager outposts spawn pillagers (including patrol captains), and nether fortresses spawn skeletons, wither skeletons, blazes, and magma cubes.
  • The population control caps are effectively 1 higher for structure spawn attempts.

Other types of spawning

General

  • In Creative or via a dispenser, the player can use spawn eggs to spawn most mobs. When mobs are spawned this way, all normal spawning requirements, such as light level and block type, are ignored (though monsters other than shulkers and the ender dragon still cannot be spawned in peaceful).
  • Any entity can be spawned using the /summon command.

Passive mobs

Mob Spawning
An agent spawns when using a code connection.‌
Spawn when using the corresponding bucket of aquatic mob.
Spawn when a bee nest or beehive is broken without Silk Touch.
Spawns when a red mooshroom is struck by lightning, and vice-versa.
Spawns in the vicinity of a player near a village.
A thrown egg spawns baby chickens.
Can be made to spawn if a player builds the proper structure out of blocks. They can also be created by an enderman.
Spawn when breeding a horse and a donkey.
Are part of Tutorial Worlds.‌
Can spawn during thunderstorms, trigger a skeleton trap.
Sniffer eggs hatch and spawn snifflets.
Turtle eggs hatch and spawn baby turtles.

Hostile mobs

Mob Spawning
A monster spawner causes mobs to spawn constantly in the area around it.
A trial spawner or ominous trial spawner causes their respective mob to spawn during a normal Trial or an ominous trial.
If a creeper gets struck by lightning, it becomes charged.
A creaking heart found in the pale garden needs to be placed by 2 correctly orientated pale oak logs. When met these conditions, they will activate and spawn a creaking during the night.
Can spawn randomly when a player uses an ender pearl.
Can spawn as part of raids or patrols.
Can spawn after player does not sleep or die for at least 3 days. (In Bedrock Edition phantoms are spawned by the environmental spawning algorithm like other monsters. They are subject to the monster cap, and they count toward the monster cap).
Killing medium and large slimes or magma cubes spawns 2-4 more, but in a smaller size.
Entities with the status effect Infested have a 10% chance to spawn 1-2 silverfish when hurt.
An infested block spawns a silverfish if broken, or if a nearby silverfish is attacked.
Entities with the status effect Oozing will spawn 2 medium slimes on death.
Skeletons spawn as 20% of naturally-spawning strays.
Spawn from skeleton traps.
When a player activates a naturally generated sculk shrieker four times or more.
When a villager gets struck by lightning, it is replaced by a newly spawned witch.
Can be made to spawn if a player builds the proper structure out of blocks.
Zombies spawn as 20% of naturally-spawning husks.‌
Can spawn reinforcement when hurt.‌
Zombie villagers spawn as 5% of naturally-spawning zombies.

A villager killed by a zombie has a 50% chance of becoming a zombie villager in normal difficulty, and 100% chance in hard difficulty.

Can spawn from nether portals in the Overworld. Lighting and player proximity don't prevent this.

When a pig gets struck by lightning, it is replaced by a newly spawned zombified piglin.

If a piglin or hoglin is transported to the Overworld or the End, after 15 seconds they transform into zombified piglins or zoglins, respectively.

Despawning

This article is about Mob Despawning. For Item Despawning, see Item § Behavior.

Java Edition

Various mob spawning ranges, illustrated.

All monster, ambient, and aquatic mobs excluding shulkers, withers, elder guardians, and ender dragons despawn unless they have been marked persistent. Other mobs that are not hostile, ambient, or aquatic that do despawn include ocelots, stray cats, wandering traders, and untamed trader llamas.

  • A mob that has had no player within 32 blocks of it for more than 30 seconds, or 10 seconds if in high light levels (over 12) for monsters, has a 1⁄800 chance of despawning on each game tick (1⁄20 of a second), which is a 2.47% chance per second. Therefore, the mob population declines so that half remains after 27.75 seconds, and the average lifetime of monsters not within 32 blocks of a player is 40 seconds (after the initial 30 seconds have elapsed). The game uses an inactivity counter to tell whether a mob should be despawned or not.
    • The inactivity counter is used to track how long a mob has not taken any action. It also controls whether certain monsters can walk randomly. When the inactivity counter is over 100, all mobs except iron golems, villagers, axolotls, camels, frogs, goats, sniffers, hoglins, zoglins, piglins, piglin brutes, wardens, and breezes will not walk randomly.
      • The inactivity counter increases by 1 per game tick for all monsters, plus an additional 2 per game tick for mobs with an internal light level over 12, and an additional 2 per game tick for all illagers and their allies. The inactivity counter is reset if one of the following conditions is met:
        • The mob is less than 32 blocks from the nearest player.
        • The mob is damaged, regardless of the damage type, which resets the counter.
        • The mob is the wither.
        • Pillagers and piglins pull their crossbows.
        • Illagers target iron golems and players during raids.
        • Illagers sweep through villages during raids.
        • Vindicators break down doors.
      • Due to the existence of the inactivity counter, mobs outside 32 blocks but within 128 blocks have a minimum survival time. For normal mobs that can be despawned, they can only be despawned after being 32 blocks away from the player for 600 game ticks (30 seconds), and will be despawned after an average of 1400 game ticks (70 seconds); for illagers, ravagers, vexes, witches, and monsters in bright places that can be despawned, they can only be despawned after being 32 blocks away from the player for at least 200 game ticks (10 seconds), and will be despawned after an average of 1000 game ticks (50 seconds).
  • Mobs other than fish despawn immediately if no player is within 128 blocks of it, while fish despawn if no player is within 64 blocks.[2]
    • This is a Euclidean sphere, not a cylinder from map top to bottom and not a taxicab sphere (an octahedron). Example: A mob at 0/y/0 remains at least 10 seconds (as above) if the player moves to 65/y/65 (real distance 91.9), but despawns immediately if the player moves to 91/y/91 (real distance 128.7).
    • The chunk the mob is in must still be loaded for the mob to despawn. Otherwise, the mob is saved until the chunk is loaded again. For example, if a player enters a nether portal while being chased by a spider, the spider is saved, and it resumes chasing the player coming back through the same portal. In the case of a player reloading chunks, the loading happens before the player is added, meaning they may despawn.
  • All mobs (including persistent mobs) despawn immediately at Y=-128 and below.
  • Ocelots and most monster mobs (including those that are holding items) despawn if the difficulty is set to Peaceful, regardless of where the player is located. Monster mobs that do not despawn include hoglins, piglins, and shulkers in all editions, as well as piglin brutes in Bedrock Edition.
  • For despawning to occur, there must be at least one non-spectator player in the dimension.
  • Chickens that originally spawned as chicken jockeys follow zombie despawn rules, rather than chicken despawn rules.
  • Wandering traders and trader llamas despawn after 40-60 minutes (2-3 in game days). They also despawn sooner if all the trades are locked.‌
  • Endermites despawn after 2 minutes unless named with a name tag or have persistent tag.
  • Wardens despawn after 1 minute if they couldn't detect a vibration or smell by any mob or player.

Mobs are persistent, meaning they do not despawn and do not count toward the respective mob caps, when they:

  • are a passenger to another mob.
  • are riding a boat or a minecart.[7]
  • spawned as part of a generated structure.
  • have had something added to their inventory, including having something dispensed upon them (such as a saddle) or something they have picked up, but never for anything they spawn with. This includes dolphins playing with items.
  • have been named with a name tag. However, one created from a renamed spawn egg does despawn as normal.
  • have had the NBT tag {PersistenceRequired: 1b} set on them, whether by being summoned with it, or by being set manually with /data merge or /data modify. This is also the only way to prevent wandering traders from despawning.

The following mobs have their despawning prevented​, and do not count towards their respective mob caps:

Bedrock Edition

In Bedrock Edition, like Java, despawning occurs based on distance and chance.

  • On simulation distances 6 and higher, almost all environmentally spawned mobs immediately despawn when they are either (1) in a chunk at the edge of the simulation distance (technically, a chunk not fully surrounded by 8 chunks that were simulated on the last game tick), or (2) more than 128 blocks from the nearest player.
  • On simulation distance 4, mobs immediately despawn when they are more than 44 blocks from the nearest player.
  • Fish despawn at a shorter distance, when they are more than 40 blocks from the nearest player on all simulation distances.
  • Mobs more than 32 blocks from the nearest player have a 1 in 800 chance to despawn on each game tick if they have not taken damage for 30 seconds.
  • All mobs (including persisent mobs) despawn immediately at Y=-128 and below.

Mobs with persistence do not despawn. Mobs gain persistence in the following ways:

The following entities always have persistence:

History

This section is missing information about: Bedrock Edition history.
 
Please expand the section to include this information. Further details may exist on the talk page.
Java Edition Classic
August 25, 2009Mobs shown to spawn in groups.
Java Edition Indev
0.3120100204-2027Mob spawning is now determined by light level. Hostile mobs spawn only in dark areas, and passive mobs spawn only in bright areas.
Java Edition Infdev
20100227-1414Mob spawning is removed.
20100316Mobs are spawned by a arrow hitting a block.
20100413-1949Mobs can no longer be spawned by a arrow hitting a block.
20100415Mob spawning is readded and mobs spawn often.
20100420Mob spawning is less often.
Java Edition Alpha
v1.2.0?The mob spawning algorithm has been changed. Trying to spawn mobs inside a solid block no longer causes that entire spawn cycle to bail out.
The chunk 0,0 (X 0-15 and Z 0-15) is no longer always the first chunk evaluated for mob spawning. Previously, if one built a dark room inside that chunk, almost all mobs would spawn there as there was no chance of the algorithm bailing out before reaching that chunk.
Hostile mobs can now spawn in higher light levels at lower depths, using the formula 16 − (Layer / 8). At level 8 and below, mobs could spawn even in sunlight.
v1.2.1Hostile mobs can no longer spawn in higher light levels at lower depths.
?The spawning area used to be 17x17 chunks rather than 15x15. The area was reduced, but the old size is still used to calculate mob caps.
It was not always possible to funnel mobs into a spawning room by preventing them from spawning elsewhere. Some older sources of information about spawning might make reference to this.
Large amounts of empty space used to encourage spawning in the general area. This remains true on a smaller scale, and only horizontally, due to pack spawning.
Java Edition Beta
1.8Pre-releasePreviously, mob spawning was determined by light level rather than the current chunk properties. This was no longer the case in Beta 1.8. In a pre-Beta 1.8 world, hostile mobs would spawn in light level 7 or lower while friendly mobs would spawn in light levels 9 or higher. Because of this, hostile mobs had a slight chance of spawning even though it was light due to them spawning in the air where there was little light. If you had a lot of torches down, go down to your mine, then return, you would have a tendency to find your house having some cows, pigs, chickens or sheep running about.
Java Edition
1.4.212w32aAdded the game rule doMobSpawning to toggle mob spawning.
1.814w25aMost restrictions on the pack location are removed. Formerly it had to be an air block, now any non-opaque block suffices.
1.915w46aWhen spawning mobs, the spawning block cannot block movement (formerly just had to be non-opaque) and cannot be any type of rail. Also the block above can no longer be liquid. Mobs can no longer spawn in blocks containing any type of rails, buttons, tripwire hooks, pressure plates, levers, redstone torches, redstone repeaters, comparators, or redstone dust.
pre2Pack spawning mechanics adjusted, "12 attempts" is now "up to 12 attempts" and is even more heavily weighted toward the center.
1.1519w37aWhen breedable mobs spawn naturally in a group, the group now sometimes includes babies. (Has a 5% or 10% chance depending on the animal.)
1.1620w18aMobs that are riders of other mobs and entities (like boats and minecarts) no longer despawn.
Added the spawn cost/charge system that reduces hostile mob spawn rates in soul sand valley and warped forest.
Added a new section to the debug screen, which covers the spawning of mobs in each category.
1.1721w13aAdded a new mob cap category for axolotls and glow squids.
1.18Experimental Snapshot 1Block light level now must be 0 for many hostile mobs to spawn (the sky light can still prevent these mobs from spawning like before).
experimental snapshot 3Mob spawning is now consistent at all altitudes, making spawn rates at all Y-levels approximately equal to the previous spawn rate at Y=64.
Added per-player mob caps.
experimental snapshot 5The spawn rate changes in experimental snapshot 3 have been reverted.
21w37aAxolotls now have their own mob cap, separate from glow squids.
21w40aAxolotls now spawn only when there is a clay block less than five blocks below the spawning space.
1.18.222w07aAquatic mobs now spawn only if the block above is a non-waterlogged water block, preventing fish from spawning inside bubble elevators.
Legacy Console Edition
Xbox 360Xbox OnePS3PS4PS VitaWii USwitch
TU1CU11.001.001.00Patch 11.0.1Added mob spawning.
TU19CU71.121.121.12Added a mob spawning host option
TU46CU361.381.381.38Patch 15Mobs no longer spawn on rails.

Issues

Issues relating to "Mob spawning" are maintained on the bug tracker. Issues should be reported and viewed there.

Trivia

  • In Bedrock Edition, an opaque block normally causes all blocks below it to spawn cave mobs, but not if a transparent block is placed on top.

Notes

  1. ↑ This means that you can block spawns of mobs that have collisions in the block above the spawning block, which is often used in spider farms.

References

This might have refrences from when "Spawn" was just a single page covering both mob and player spawning.
  1. ↑ MCPE-146484
  2. ↑ a b "Minecraft Snapshot 20w10a" – Minecraft.net, March 4, 2020.
  3. ↑ MC-1788
  4. ↑ that is, the block situated one block above the floor block the mob will spawn onto
  5. ↑ a b c d only 8 levels, since only blocks with solid top surfaces are spawnable. See MC-202376.
  6. ↑ The 96-block horizontal limit is reported as a bug at MCPE-102197
  7. ↑ MC-182897 — Some passenger mobs don't count to the mob cap — resolved as "Works As Intended".
  8. ↑ https://bugs-legacy.mojang.com/browse/MC-124812
  9. ↑ MC-182304
  10. ↑ MCPE-70664

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