Simian beast companions include both monkeys and apes. Your simian companion could be as small as a spider monkey or as large as an ape.
Ability Scores: Strength 14, Constitution 14, Dexterity 16, Intelligence 6, Wisdom 12, Charisma 6
Size: Small or Medium (you choose at creation)
Speed: 6 squares, climb 6
Defenses: AC 14 + level, Fortitude 12 + level, Reflex 13 + level, Will 12 + level
Hit Points: 14 + 8 per level
Attack Bonus: Level + 4
Melee Basic Attack: Bite; level + 4 vs. AC; 1d6 + Strength modifier damage.
Trained Skills: Athletics, Acrobatics
Published in Dragon Magazine 392.