CurseForge · Minecraft mod
Big Brain
Improved AI for various mobs!
Quick answer
Which Big Brain release should I use?
Big Brain bigbrain-2.2.9-1.21.1.jar targets 1.21.1 with NeoForge. The project page does not say whether this file belongs on the client, dedicated server, or both. No extra mods listed for this file.
Where it goes
Is Big Brain required on the client, server, or both?
The project page does not say whether this file belongs on the client, dedicated server, or both.
The source does not explicitly classify this release as client-only or server-only.
What else does Big Brain bigbrain-2.2.9-1.21.1.jar need?
bigbrain-2.2.9-1.21.1.jar. Change the file and its required mods may change too.
This file does not list any required mods. Do not add a library just because a different file uses it.
This file does not list any required or optional mods.
Before you install it
Add Big Brain without breaking your instance.
Built for Big Brain bigbrain-2.2.9-1.21.1.jar. Pick another file and the loader, install side or required mods may change.
- 01
Stick to this file
Use bigbrain-2.2.9-1.21.1.jar. It targets 1.21.1 with NeoForge; another release may have different loader, side or dependency requirements.
- 02
Bring the mods it needs
This file does not list any required mods. Do not add a library just because a different file uses it.
- 03
Put it on the correct side
The project page does not say whether this file belongs on the client, dedicated server, or both.
- 04
Pick the file you checked
Use the “Get this file” button beside bigbrain-2.2.9-1.21.1.jar. It opens that exact file at the source.
About this project
What does Big Brain add?
About:
Big Brain is a mod that focuses on adding smarter ai for the many mobs of Minecraft!
Features: (all are configurable)
Animals
All vanilla animals except for cats and foxes will attempt to find shelter when it's night or raining. They will also alert their herd members to panic if one of them is attacked.

While all the other animals have special features, like cows giving leather, chickens having feathers that are used to make arrows, and shee giving wool that you use to build things. Pigs on the other hand don't have any advantages.
This mod changes that, pigs now have a larger litter size of 2 - 6 piglets, giving the player a reason to consider breeding pigs for their farm.

Ocelots
Ocelots now attack creepers, parrots, and phantoms to give them some purpose.
Sheep
Sheep now run away from wolves instead of acting like nothing is happening.
Polar Bears
Polar bears now attack fish.
Bees
Bees now have an animation akin to Bedrock's.

Frogs
Frogs will eat vexes.
Enemies:
Husks
Husks will now upon seeing the player burrow for some time and attempt to grab and drag the player down.
However, if a significant amount of damage is dealt while the husk is burrowing it will cancel its attack and do regular melee.
You cannot escape the husk while being grabbed but you are allowed to attack it since it has a delay between grabbing and pulling you down.
Going on a higher elevation level than the husk will tire it out and also cause it to go into regular melee stance.

Drowned
Drowned have glow layers like in Bedrock.
Pillagers
Pillager combat can get boring, most of the time they charge you with no regard for their lives.
Pillagers are still dumb with this mod, but at the very least care for their own lives.
They now run to another direction while they're reloading, they also move closer to you if they have a multishot crossbow.
Pillagers leaders in patrols also now have the ability to notice you from a farer distance by using a spyglass that they have a 50% chance of spawning with.

Snow Golems (and snowballs)
Snowballs are now able to give entities 5 seconds of freezing, which can be added up by successive shots.

All Mobs
These are changes that apply to all mobs:
-Blindness now affects mob vision, reducing their range by 90%. This stacks with other vision modifiers.
-A patch for melee mobs resetting their attack cooldown if they were in front of you has been added.
-A config option has been added to allow all mobs to attack villagers, this is disabled by default and has a blacklist included.
-Bow-wielding mobs now have a new attack pattern. Many people complain about bow-wielding mobs being frustrating to fight against. This rework is meant to help mitigate against this notion. Instead of strafing bow-wielders will instead stand still until they fire three shots. After three shots they will move to another position. If the player is too close for comfort then they will also try to find another position.
-Mobs that are able to open doors are now able to open fence gates as well.
-Baby hostile creatures have their health halved (eg, baby zombies will now have 10 health points), now you can feel a bit safer in your hardcore worlds!
-Humanoid mobs, such as piglins and zombies, are now able to jump through gaps (credits to the Mobs Attempt Parkour mod for their direct inspiration)
Frequently Asked Questions
Is this mod compatible with x?
Try them both and see! (in particular, Savage And Ravage works with this mod)
Where's the buckler?
In 1.20 it was moved to Piglin Proliferation because I personally thought it better fit the mod.
How laggy is this mod?
This mod uses the same vanilla system to add and remove ai to mobs, their performance should be equivalent. If you encounter any performance issues whilst using the mod. do report to the mod's github.
Videos
(1:03)
Project description from CurseForge.
Pick your setup
Big Brain by Minecraft version and loader
Choose the version and loader you play, then open the matching release.
1.21.1
1 loader build1.21
1 loader build1.20.2
1 loader build1.20.1
2 loader builds1.20
1 loader build1.19.4
1 loader build1.19.3
1 loader build1.19.2
2 loader builds1.19.1
1 loader build1.19
1 loader build1.18.2
1 loader buildShowing the newest 12 of 16 game versions. Older files are in the list below.
Check the dependencies, then try the file in a copied instance before changing a world you care about.
Recent files
Big Brain versions and loaders
bigbrain-2.2.9-1.21.1.jar
25 Oct 2026
bigbrain-3.0.0-26.3.0.jar
25 Oct 2026
bigbrain-1.20.1-1.7.8.jar
5 Sept 2026
bigbrain-2.2.8-1.21.1.jar
5 Sept 2026
bigbrain-2.2.7-1.21.1.jar
19 Jul 2026
bigbrain-1.20.1-1.7.7.jar
19 Jul 2026
bigbrain-2.2.6-1.21.1.jar
14 Jul 2026
bigbrain-1.20.1-1.7.6.jar
7 Dec 2025
bigbrain-1.20.1-1.7.5.jar
29 Nov 2025
bigbrain-2.2.5-1.21.1.jar
12 Jun 2025
bigbrain-2.2.4-1.21.1.jar
24 Dec 2024
bigbrain-2.2.3-1.21.jar
21 Jul 2024
Looking for an older file? The official CurseForge project page is in Resources.
