Ok so, Spiders and creepers running animation is to fast when they chase you in survival. Zombies walking animation on the other hand is just a tad faster than normal. Spiders and Zombie mobs run to the player way to fast. Not sure if creepers are to fast or are running at normal speed.

Steps to reproduce
-Make a creative world.
-Spawn a spider, creeper or zombie.
-Be just enough distance from the entity but enough distance that they also see you.
-Switch world game mode to survival.

Edit
Baby zombies are also to fast!

UPDATE 0.12.1 build 9
Creepers still have a fast running animation when in pursuit of the player.
Spiders still have a fast running animation when in pursuit of the player.
Zombies still have a running animation that is twice as fast as normal AND when in pursuit of the player.
My game difficulty is set to easy.