1.17 Pre-release 3
There was a change in the 1.17 pre releases that removes any hostility between mobs in peaceful difficulty.
Since this wasn't mentioned in the patch notes and as far as I understand it "peaceful" refers to mobs not attacking the player, I think this might be a bug.
I tested the following mob interactions:
- cats don't attack chickens or rabbits
- wolves don't attack llamas or foxes
- polar bears don't attack foxes
- snow golems don't attack shulkers
- shulkers don't fight back when attacked by a non player mob
- axolotls don't attack squid or fish
- iron golems don't attack shulkers or hoglins
- ocelots don't attack chickens
There are probably more that I don't think of.