Level 129s and level 82s can be found under the Temple where Monkey Guards are located. The level 82 version are actually called Monkey zombies and are smaller.
There are also level 98 zombie monkeys located in the inaccessible room under the Marimbo Temple (accessible after the Hard Western Provinces Diary is complete). They are also located in the cave with skeleton monkeys.
Monkey zombies appear to be green undead monkeys.
If you have a high enough Prayer and combat level, these monsters can be used for training. One can get around 100k experience per hour at higher levels. Use prayer, and when you are out run upstairs and use the altar. Make sure, however, to become a monkey using a greegree or you will be trapped by the larger monkeys up the ladder. An alternative to training here would be to bring prayer-boosting gear and use prayer potions, getting rid of the need to go upstairs and avoid the monkey guards. Remember to bring Salve amulet or Salve amulet (e), as they are undead.
Item Quantity Rarity GE market price Monkey bones (small zombie) 1 Always  Not sold Monkey bones (big zombie) 1 Always  Not sold