What is Improved Mob Spawns?
This mod will change the mob spawn of several mobs. One example is that spider jockeys (shown below) are 5 times less rare.
This mod makes several changes to the way mobs are spawned.
How to install:
Improved Mob Spawns Mod Download Links:
For Minecraft 1.7.2
For Minecraft 1.6.4
For Minecraft 1.6.2
For Minecraft 1.5.2