No I get what you mean. There feels like theres hardly any mobs on the surface and in caves. I don't think it has anything to do with the new zero light level requirement.
I think this might mostly be due to how many caves and how large they are now. So there's far more room and space for mobs to spawn. Coupled together with the mob cap, I think this really hinders the number of hostile mobs spawning....
I wish they increased the frequency of hostile mobs spawning again :/
No I get what you mean. There feels like theres hardly any mobs on the surface and in caves. I don't think it has anything to do with the new zero light level requirement.
I think this might mostly be due to how many caves and how large they are now. So there's far more room and space for mobs to spawn. Coupled together with the mob cap, I think this really hinders the number of hostile mobs spawning....
I wish they increased the frequency of hostile mobs spawning again :/
Even when I modded the game (1.6) to have 3 times the vanilla ground depth, giving about 3.5 times more space between lava level and sea level and certainly far more caves than 1.18, especially when it comes to surface area as they were basically the same as vanilla (mostly relatively narrow tunnels, plus the occasional much larger caves and ravines), I still encountered plenty of mobs, a couple hundred per play session, if still less than what I usually see, and this may be because of how thoroughly I light up caves, so on average about half the volume around me has been spawnproofed (in general as I explore a given cave system the number of mobs I encounter increases as there are less dark areas left; I don't remember as this was 8 years ago but I'd assume that it was more pronounced in DHT/THT due to cave systems being much larger but also more isolated).
Here is a look at what "TripleHeightTerrain" was like:
This is actually just an "average" cave system - a massively upscaled version of what you could find in vanilla 1.6.4, with tens of thousands of torches required to fully light one up, plus the occasional much wider tunnels and larger ravines:
These are from the side of the world, helping show how deep it actually is; the first one shows a depth of 201 blocks from the surface, while the "tiny" trees near the top-left are giant jungle trees, the biggest trees in the game (even nearly 10 years after they were added):
That said, in TMCW I did make changes to mob spawning to increase then number the player encounters despite a significantly greater volume of caves, about double that of vanilla (which itself has about 20% more air than 1.7+ and mainly differs in the size and density of individual cave clusters and number of mineshafts); the (de)spawn radius was reduced from 128 to 96 (the mobs with the furthest line of sight are Endermen and Ghasts, at 64 blocks, and in 1.6.4 the (internal) server doesn't send mobs to the client unless they are within 80 blocks of the player) and the "no-spawn" zone around the player was reduced from 24 to 16 blocks, which together roughly doubles the density of mobs near the player without actually increasing the mob cap, more than offsetting a doubling in underground air volume (though the increase in surface area is closer to 1.33 based on the increase in ore exposure per chunk). More recently, I reduced the vertical spawn range in the Nether to a 64 block range centered on the player (unless they are too low or high, then the min/max is limited to 1-125) to simulate the mob density in the Overworld (59 blocks deep between lava level and sea level, a bit more for the typical surface).
wow those terrain picks look pretty cool. With triple terrain does it not make finding ores like redstone and diamonds much harder and time consuming to get to sufficiently low enough levels?
So it seem that the best answer would be for Mojang to up the spawn rate, and fiddle around with min/max spawn radii.
wow those terrain picks look pretty cool. With triple terrain does it not make finding ores like redstone and diamonds much harder and time consuming to get to sufficiently low enough levels?
So it seem that the best answer would be for Mojang to up the spawn rate, and fiddle around with min/max spawn radii.
It doesn't take much longer to dig a tunnel down to diamond level; I literally just dug straight down, without even making the hole 2 blocks wide , which only required about as many blocks removed as digging a staircase in vanilla, which requires 3 blocks per block down; despite the size of cave systems there are very large open areas (this is also true of pre-1.7 cave generation, on the left, and likewise I've had no issues making substantial mines below lava level), though I did come within 7-8 blocks of a 65 block deep ravine, and even then I'd have fallen on a ledge near the top until going a couple more blocks over:
As for caves, there was about 3 times more of all ores exposed above lava level and while I might have spent days exploring the higher levels with only coal and iron once I got deeper down I could find rarer ores at a much higher rate (this explains why Mojang made the changes they did in 1.18; as far as I'm concerned the overall relative ore amounts being close to vanilla is all that matters as I only cave for fun).
The main reason why I went back to a near-vanilla underground depth (with cave lava level lowered from 11 to 4) is the aforementioned lack of variety in ores across much of the depth, as well as surface/biome generation due to how much longer it took to explore a given area (this is even more true in TMCW, where various biomes have biome-specific underground blocks, as well as a much greater variety in biomes in general; my early mods like THT only changed the underground and/or ground depth), as seen in this comparison of all of my "caving" worlds; THT is my smallest world but would have about 4 times the area if it had the same relative volume as vanilla (World1v3 had twice the vanilla ground depth; the name of the world refers to the fact it used the same seed as World1, my first world; even TMCWv1 used the same seed but at that point I started modding biomes and surface terrain):
I've also seen many arguments for a deeper underground to allow for larger caves but in fact the largest caves in any of my mods are actually in TMCW, with an effective ground depth of 59 layers; the only real benefit of a deeper underground is caves with a greater vertical extent but I don't feel that such deep caves add anything to exploration; once you exceed 15 blocks you can't even see the ceiling anyway unless you pillar up so depth becomes almost irrelevant unless you take the effort to light up the ceiling (ravines are a bit different as they have ledges along the sides); in fact, in TMCW as caves get wider their relative height decreases (the widest caves reach a width of 85 blocks at which point the height is 60% of the width, or 51 blocks; likewise, the deepest possible ravine is about 70 blocks deep instead of 117 blocks if they used the vanilla height ratio of 3:1. While this allows for ravines from the surface down to lava level they are quite rare as they need to be within the right altitude range (y=27-39). Even the largest cave I know of in TMCWv5 (not released yet) has a volume of 1.1 million blocks but only breaks the surface at one end:
This is a chart of all the variations of caves in TMCWv5, which includes the giant cave shown above near the bottom-center; it is still smaller in volume and area extent than a giant cave region, which averages about 1.7 million blocks, but are technically not a single cave (they consist of 84-85 moderately large caves similar to the smaller caves around the giant cave; for another perspective of scale the smallest cave in the upper-left of the area under "Large Caves" is representative of the largest caves you can find in vanilla, while colossal cave systems are representative of the largest and densest cave systems):
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im playing a multiplayer server java version 1.18.1 vanilla on hard mode and as soon as the sun is down the hostile mobs spawn in crazy numbers. way more than just groups of 3 or 4 here and there. i haven't tried it on normal mode though. i know that in my regular single player world which is vanilla java normal, from 1.14 to 1.17 hostile mob spawning has changed radically a few times. I havent updated to 1.18.1 on that world yet.
I like the idea that if I put a f*ing torch down I'm going to be safe from things spawning immediately upon me.
This was never an issue - mobs have never been able to spawn within 24 blocks of a player so there was never any need to use torches as long as the room you was no more than 24 blocks across (circular, or a 17x17 block square when factoring in diagonals; both assume that the player can be anywhere within the room) - even the brightest light source is only effective up to 14 blocks away by taxicab, which covers a much smaller area/volume than a circle/sphere of the same radius:
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
Also, unless you have your monitor's brightness insanely cranked up or edited gamma in options.txt (which should not be allowed) you'll still need light just to see - when caving I naturally place torches close enough together that the area is almost totally spawnproofed with a light level of 8 or higher, but my only objective is to light up the area for visibility (this is also with brightness set to Bright; on Moody I'd probably place at least 4x as many torches as they only have about half the range for good visibility):
The actual light level where I place a torch is around 3-4, corresponding to around 10 blocks apart, as I place them when branch-mining in a 1 block wide tunnel (in open areas you'll need to place them closer, ideally in a staggered pattern as visible in this example, which naturally evolves because of the way light spreads out from light sources and the fact I place them to see; likewise, you can see some areas that are too dark (for the old spawning system, which still applies to me as I play in 1.6.4), but not too dark to require placing torches to see (mobs are still less likely to spawn in these areas because the failure rate is (level/8); from 0% at 0 to 50% at 4 to 100% at 8).
No I get what you mean. There feels like theres hardly any mobs on the surface and in caves. I don't think it has anything to do with the new zero light level requirement.
I think this might mostly be due to how many caves and how large they are now. So there's far more room and space for mobs to spawn. Coupled together with the mob cap, I think this really hinders the number of hostile mobs spawning....
I wish they increased the frequency of hostile mobs spawning again :/
Related to this:
There was a bug starting back on 1.17 or earlier (Bedrock for sure, not sure if it happened in Java as well) that because mobs like zombies could pick up items, it was causing severe lag for some world generations because they were getting stuck in underground caves or elsewhere in rendered chunks and would never despawn and so they would just keep building up until some sort of critical mass was achieved.
During that time period, I had it happen to me - between my newly built aquarium and the hidden mobs that wouldn’t despawn, my game started lagging really badly. I traced it back to me building the aquarium, but beyond that I had no clue.
I ended up killing most of my fish and unnecessary tamed animals because I couldn’t figure out what was happening and it wasn’t until I went caving and returned to room that had running water that I found a party of zombies along with some zombie villagers and skeletons all hanging around… still… and carrying various items.
They had spawned in during my previous visit and I had blocked off the room and run off because I hadn’t been in the mood to deal with them and figured they would despawn on their own, but they hadn’t and were still waiting for me. I torched and killed them all and found a dungeon nearby and I torched and killed all those mobs, too, and when I finally returned to the surface, the lag had improved greatly.
After all that happened, I went to look at the bug reports and sure enough, other people had described similar issues and I don’t think it’s gone away yet, if some of the new bug reports are any indication.
There was a bug starting back on 1.17 or earlier (Bedrock for sure, not sure if it happened in Java as well) that because mobs like zombies could pick up items, it was causing severe lag for some world generations because they were getting stuck in underground caves or elsewhere in rendered chunks and would never despawn and so they would just keep building up until some sort of critical mass was achieved.
This has existed for as long as zombies (and skeletons, but only armor and swords, at least as of Java 1.6.4) have been able to pick up items but hasn't caused any issues, even on my first world, with over 180 real-time days of playtime, but I do light up virtually every cave in the areas I explore (I do still miss some areas and otherwise will never find non-interconnected caves, up to entire cave systems or mineshaft complexes, as I generally only explore interconnected caves, or caves connected to the surface once I've explored everything else around them).
In particular, when chicken jockeys were added in 1.7.4 they would lay eggs and zombies would pick them up, with up to thousands accumulating in a relatively short time (the bug report mentions multiplayer but singleplayer can have the same issue, especially if you AFK a lot):
Also, this is from an MCEdit analysis of my first world, with 349 zombies present, most of which will have picked up items, and to a much lesser extent, some of the 23 skeletons present (otherwise, there are on average the same number of creepers, spiders, skeletons, and zombies; zombies only seem much more common due to their larger aggro range and calling for help); there are also 52 endermen which haven't despawned due to making them not despawn when holding a block (a feature added in a later vanilla version; I do increase/decrease the rate of attempts to place/take blocks to minimize this):
Note that there are over 38,000 entities total, mostly passive mobs, so on a large scale the effect of zombies is insignificant, but it does tend to be localized to areas players frequent (this would be around my bases, where I only spend a small part of my time, otherwise I'm constantly moving around while caving). Even dropped items, which despawn after 5 minutes, are present in far greater numbers than zombies (other than eggs many are drops from mobs I killed while others, like nearly a thousand rails, are from world generation and are in the outermost chunks, which do not process entities).
Also, ocelots, at least in 1.6.4, can cause similar issues; I've seen over 300 within loaded chunks in areas I explored since while they are passive mobs, and count towards their respective cap, they are on the hostile mob spawn list so as long as the cap isn't filled the game will keep attempting to spawn mobs, and unlike hostile mobs they do not automatically despawn when far from the player, only randomly (I later fixed this by adding a hard limit of 25 ocelots in loaded chunks but there are still thousands of ocelots, mostly in jungles I explored before then, plus their 2 minute (30 seconds for most mobs) despawn timer is reset every time they are unloaded or you come within 32 blocks, so even areas I regularly pass though, along my rail system, continue to have a high number of ocelots).
I feel
1.18 has completely changed how Mob spawning around light levels work
Hello,
We appreciate your honest opinions on the new update,
But this thread could benefit from some more detail?
That would be appreciated
hi I’m older and slightly more mature ignore my old posts pls
Amazing!
I run a private minecraft server called Nostalgik Vanilla for ages of 21 and up. Anyone that is interested in it, just contact me
Now the hostile creatures spawn only in totallly dark
No I get what you mean. There feels like theres hardly any mobs on the surface and in caves. I don't think it has anything to do with the new zero light level requirement.
I think this might mostly be due to how many caves and how large they are now. So there's far more room and space for mobs to spawn. Coupled together with the mob cap, I think this really hinders the number of hostile mobs spawning....
I wish they increased the frequency of hostile mobs spawning again :/
Even when I modded the game (1.6) to have 3 times the vanilla ground depth, giving about 3.5 times more space between lava level and sea level and certainly far more caves than 1.18, especially when it comes to surface area as they were basically the same as vanilla (mostly relatively narrow tunnels, plus the occasional much larger caves and ravines), I still encountered plenty of mobs, a couple hundred per play session, if still less than what I usually see, and this may be because of how thoroughly I light up caves, so on average about half the volume around me has been spawnproofed (in general as I explore a given cave system the number of mobs I encounter increases as there are less dark areas left; I don't remember as this was 8 years ago but I'd assume that it was more pronounced in DHT/THT due to cave systems being much larger but also more isolated).
Here is a look at what "TripleHeightTerrain" was like:
This is actually just an "average" cave system - a massively upscaled version of what you could find in vanilla 1.6.4, with tens of thousands of torches required to fully light one up, plus the occasional much wider tunnels and larger ravines:
These are from the side of the world, helping show how deep it actually is; the first one shows a depth of 201 blocks from the surface, while the "tiny" trees near the top-left are giant jungle trees, the biggest trees in the game (even nearly 10 years after they were added):
That said, in TMCW I did make changes to mob spawning to increase then number the player encounters despite a significantly greater volume of caves, about double that of vanilla (which itself has about 20% more air than 1.7+ and mainly differs in the size and density of individual cave clusters and number of mineshafts); the (de)spawn radius was reduced from 128 to 96 (the mobs with the furthest line of sight are Endermen and Ghasts, at 64 blocks, and in 1.6.4 the (internal) server doesn't send mobs to the client unless they are within 80 blocks of the player) and the "no-spawn" zone around the player was reduced from 24 to 16 blocks, which together roughly doubles the density of mobs near the player without actually increasing the mob cap, more than offsetting a doubling in underground air volume (though the increase in surface area is closer to 1.33 based on the increase in ore exposure per chunk). More recently, I reduced the vertical spawn range in the Nether to a 64 block range centered on the player (unless they are too low or high, then the min/max is limited to 1-125) to simulate the mob density in the Overworld (59 blocks deep between lava level and sea level, a bit more for the typical surface).
TheMasterCaver's First World - possibly the most caved-out world in Minecraft history - includes world download.
TheMasterCaver's World - my own version of Minecraft largely based on my views of how the game should have evolved since 1.6.4.
Why do I still play in 1.6.4?
wow those terrain picks look pretty cool. With triple terrain does it not make finding ores like redstone and diamonds much harder and time consuming to get to sufficiently low enough levels?
So it seem that the best answer would be for Mojang to up the spawn rate, and fiddle around with min/max spawn radii.
It doesn't take much longer to dig a tunnel down to diamond level; I literally just dug straight down, without even making the hole 2 blocks wide , which only required about as many blocks removed as digging a staircase in vanilla, which requires 3 blocks per block down; despite the size of cave systems there are very large open areas (this is also true of pre-1.7 cave generation, on the left, and likewise I've had no issues making substantial mines below lava level), though I did come within 7-8 blocks of a 65 block deep ravine, and even then I'd have fallen on a ledge near the top until going a couple more blocks over:
As for caves, there was about 3 times more of all ores exposed above lava level and while I might have spent days exploring the higher levels with only coal and iron once I got deeper down I could find rarer ores at a much higher rate (this explains why Mojang made the changes they did in 1.18; as far as I'm concerned the overall relative ore amounts being close to vanilla is all that matters as I only cave for fun).
The main reason why I went back to a near-vanilla underground depth (with cave lava level lowered from 11 to 4) is the aforementioned lack of variety in ores across much of the depth, as well as surface/biome generation due to how much longer it took to explore a given area (this is even more true in TMCW, where various biomes have biome-specific underground blocks, as well as a much greater variety in biomes in general; my early mods like THT only changed the underground and/or ground depth), as seen in this comparison of all of my "caving" worlds; THT is my smallest world but would have about 4 times the area if it had the same relative volume as vanilla (World1v3 had twice the vanilla ground depth; the name of the world refers to the fact it used the same seed as World1, my first world; even TMCWv1 used the same seed but at that point I started modding biomes and surface terrain):
I've also seen many arguments for a deeper underground to allow for larger caves but in fact the largest caves in any of my mods are actually in TMCW, with an effective ground depth of 59 layers; the only real benefit of a deeper underground is caves with a greater vertical extent but I don't feel that such deep caves add anything to exploration; once you exceed 15 blocks you can't even see the ceiling anyway unless you pillar up so depth becomes almost irrelevant unless you take the effort to light up the ceiling (ravines are a bit different as they have ledges along the sides); in fact, in TMCW as caves get wider their relative height decreases (the widest caves reach a width of 85 blocks at which point the height is 60% of the width, or 51 blocks; likewise, the deepest possible ravine is about 70 blocks deep instead of 117 blocks if they used the vanilla height ratio of 3:1. While this allows for ravines from the surface down to lava level they are quite rare as they need to be within the right altitude range (y=27-39). Even the largest cave I know of in TMCWv5 (not released yet) has a volume of 1.1 million blocks but only breaks the surface at one end:
This is a chart of all the variations of caves in TMCWv5, which includes the giant cave shown above near the bottom-center; it is still smaller in volume and area extent than a giant cave region, which averages about 1.7 million blocks, but are technically not a single cave (they consist of 84-85 moderately large caves similar to the smaller caves around the giant cave; for another perspective of scale the smallest cave in the upper-left of the area under "Large Caves" is representative of the largest caves you can find in vanilla, while colossal cave systems are representative of the largest and densest cave systems):
TheMasterCaver's First World - possibly the most caved-out world in Minecraft history - includes world download.
TheMasterCaver's World - my own version of Minecraft largely based on my views of how the game should have evolved since 1.6.4.
Why do I still play in 1.6.4?
im playing a multiplayer server java version 1.18.1 vanilla on hard mode and as soon as the sun is down the hostile mobs spawn in crazy numbers. way more than just groups of 3 or 4 here and there. i haven't tried it on normal mode though. i know that in my regular single player world which is vanilla java normal, from 1.14 to 1.17 hostile mob spawning has changed radically a few times. I havent updated to 1.18.1 on that world yet.
This was never an issue - mobs have never been able to spawn within 24 blocks of a player so there was never any need to use torches as long as the room you was no more than 24 blocks across (circular, or a 17x17 block square when factoring in diagonals; both assume that the player can be anywhere within the room) - even the brightest light source is only effective up to 14 blocks away by taxicab, which covers a much smaller area/volume than a circle/sphere of the same radius:
Also, unless you have your monitor's brightness insanely cranked up or edited gamma in options.txt (which should not be allowed) you'll still need light just to see - when caving I naturally place torches close enough together that the area is almost totally spawnproofed with a light level of 8 or higher, but my only objective is to light up the area for visibility (this is also with brightness set to Bright; on Moody I'd probably place at least 4x as many torches as they only have about half the range for good visibility):
The actual light level where I place a torch is around 3-4, corresponding to around 10 blocks apart, as I place them when branch-mining in a 1 block wide tunnel (in open areas you'll need to place them closer, ideally in a staggered pattern as visible in this example, which naturally evolves because of the way light spreads out from light sources and the fact I place them to see; likewise, you can see some areas that are too dark (for the old spawning system, which still applies to me as I play in 1.6.4), but not too dark to require placing torches to see (mobs are still less likely to spawn in these areas because the failure rate is (level/8); from 0% at 0 to 50% at 4 to 100% at 8).
TheMasterCaver's First World - possibly the most caved-out world in Minecraft history - includes world download.
TheMasterCaver's World - my own version of Minecraft largely based on my views of how the game should have evolved since 1.6.4.
Why do I still play in 1.6.4?
Related to this:
There was a bug starting back on 1.17 or earlier (Bedrock for sure, not sure if it happened in Java as well) that because mobs like zombies could pick up items, it was causing severe lag for some world generations because they were getting stuck in underground caves or elsewhere in rendered chunks and would never despawn and so they would just keep building up until some sort of critical mass was achieved.
During that time period, I had it happen to me - between my newly built aquarium and the hidden mobs that wouldn’t despawn, my game started lagging really badly. I traced it back to me building the aquarium, but beyond that I had no clue.
I ended up killing most of my fish and unnecessary tamed animals because I couldn’t figure out what was happening and it wasn’t until I went caving and returned to room that had running water that I found a party of zombies along with some zombie villagers and skeletons all hanging around… still… and carrying various items.
They had spawned in during my previous visit and I had blocked off the room and run off because I hadn’t been in the mood to deal with them and figured they would despawn on their own, but they hadn’t and were still waiting for me. I torched and killed them all and found a dungeon nearby and I torched and killed all those mobs, too, and when I finally returned to the surface, the lag had improved greatly.
After all that happened, I went to look at the bug reports and sure enough, other people had described similar issues and I don’t think it’s gone away yet, if some of the new bug reports are any indication.
This has existed for as long as zombies (and skeletons, but only armor and swords, at least as of Java 1.6.4) have been able to pick up items but hasn't caused any issues, even on my first world, with over 180 real-time days of playtime, but I do light up virtually every cave in the areas I explore (I do still miss some areas and otherwise will never find non-interconnected caves, up to entire cave systems or mineshaft complexes, as I generally only explore interconnected caves, or caves connected to the surface once I've explored everything else around them).
In particular, when chicken jockeys were added in 1.7.4 they would lay eggs and zombies would pick them up, with up to thousands accumulating in a relatively short time (the bug report mentions multiplayer but singleplayer can have the same issue, especially if you AFK a lot):
MC-42174 Chicken Jockeys causing lag on Multiplayer servers
Also, this is from an MCEdit analysis of my first world, with 349 zombies present, most of which will have picked up items, and to a much lesser extent, some of the 23 skeletons present (otherwise, there are on average the same number of creepers, spiders, skeletons, and zombies; zombies only seem much more common due to their larger aggro range and calling for help); there are also 52 endermen which haven't despawned due to making them not despawn when holding a block (a feature added in a later vanilla version; I do increase/decrease the rate of attempts to place/take blocks to minimize this):
,<Entities>,38289
Arrow,Arrow,218
Bat,Bat,16
Boat,Boat,18
CaveSpider,CaveSpider,4
Chicken,Chicken,6816
Cow,Cow,4709
Creeper,Creeper,11
Enderman,Enderman,52
EntityHorse,EntityHorse,232
Item,Apple,10
Item,Arrow,170
Item,Bone,144
Item,Bow,19
Item,Brown Mushroom,27
Item,Cactus,2
Item,Carrot,1
Item,Chainmail Boots,1
Item,Chainmail Chestplate,1
Item,Chainmail Helmet,1
Item,Chainmail Leggings,1
Item,Coal,4
Item,Cobblestone,5
Item,Dirt,27
Item,Egg,1251
Item,Feather,4
Item,Flint,10
Item,Flower,5
Item,Glass Bottle,3
Item,Golden Boots,2
Item,Golden Chestplate,4
Item,Golden Helmet,1
Item,Golden Leggings,1
Item,Gravel,34
Item,Gunpowder,94
Item,Ink Sack,17
Item,Iron Axe,1
Item,Iron Sword,1
Item,Jungle Sapling,3
Item,Leather Boots,2
Item,Leather Cap,1
Item,Leather Pants,2
Item,Leather Tunic,1
Item,Lily Pad,3
Item,Oak Sapling,100
Item,Potato,1
Item,Rail,911
Item,Raw Chicken,2
Item,Raw Porkchop,5
Item,Red Mushroom,25
Item,Redstone,4
Item,Rose,1
Item,Rotten Flesh,320
Item,Sand,12
Item,Seeds,24
Item,Slimeball,245
Item,Spider Eye,22
Item,Stick,1
Item,Stone,2
Item,String,189
Item,Sugar,1
Item,Sugar Canes,4
ItemFrame,ItemFrame,20
MinecartChest,MinecartChest,4453
MinecartRideable,MinecartRideable,26
MushroomCow,MushroomCow,76
Ozelot,Ozelot,3271
Pig,Pig,6424
Sheep,Sheep,7341
Skeleton,Skeleton,23
Slime,Slime,1
Spider,Spider,12
Squid,Squid,6
Villager,Villager,113
VillagerGolem,VillagerGolem,2
Witch,Witch,5
Wolf,Wolf,167
XPOrb,XPOrb,202
Zombie,Zombie,349
Note that there are over 38,000 entities total, mostly passive mobs, so on a large scale the effect of zombies is insignificant, but it does tend to be localized to areas players frequent (this would be around my bases, where I only spend a small part of my time, otherwise I'm constantly moving around while caving). Even dropped items, which despawn after 5 minutes, are present in far greater numbers than zombies (other than eggs many are drops from mobs I killed while others, like nearly a thousand rails, are from world generation and are in the outermost chunks, which do not process entities).
Also, ocelots, at least in 1.6.4, can cause similar issues; I've seen over 300 within loaded chunks in areas I explored since while they are passive mobs, and count towards their respective cap, they are on the hostile mob spawn list so as long as the cap isn't filled the game will keep attempting to spawn mobs, and unlike hostile mobs they do not automatically despawn when far from the player, only randomly (I later fixed this by adding a hard limit of 25 ocelots in loaded chunks but there are still thousands of ocelots, mostly in jungles I explored before then, plus their 2 minute (30 seconds for most mobs) despawn timer is reset every time they are unloaded or you come within 32 blocks, so even areas I regularly pass though, along my rail system, continue to have a high number of ocelots).
TheMasterCaver's First World - possibly the most caved-out world in Minecraft history - includes world download.
TheMasterCaver's World - my own version of Minecraft largely based on my views of how the game should have evolved since 1.6.4.
Why do I still play in 1.6.4?