Environmental enrichment for caged Rhesus macaques: photographic documentation and literature review. Contents: 1. Preface, 2. Animal welfare concerns. 2.1. Barren living quarters, 2.2. Involuntary restraint ,3. Refinement. 3.1. Animate enrichment. Group-housing. Pair-housing. Grooming-contact housing. Kindergarten. Attention from care personnel. Positive reinforcement training, 3.2. Feeding enrichment. Vegetables and fruits. Standard food ration behind a barrier or on woodchips. Expanded feeding schedule. Special food in and on gadgets. Special food mixed with a substrate, 3.3. Inanimate enrichment. Structural enrichment. Toys and playrooms. Gnawing sticks. Paper and cardboard boxes. Mirrors. Windows and light. Videos and television. Music. Water, 4. Conclusions, 5. References, 6. Photo credits. - from Amzon