Mahoney, C. J. 1992. Some thoughts on psychological enrichment. Lab Animal 21(5), 27,29,32-37.

Facilities must exercise caution when installing such climbing devices as vertically hanging or horizontally suspended ropes and chains - these must not crisscross or be too slack, because an animal can strangle its neck, limbs, or other body parts. .. even left-over breakfast cereal cartons, readily available to most staff members, can offer endless entertainment for most species. .. Isolation 'wards' for ill animals and infectious study chambers can have windows or transparent plastic panels between cages, providing visual communication without interfering with independent or filtered air-flow. .. The sanitation tray, which runs the length of the room beneath the upper tier of cages, reduces significantly the amount of light from ceiling-mounted fixtures that can penetrate to the lower cage tier; animals in the lower tier are thus relegated to a permanent state of semi-gloom (p. 32). .. Pans from rabbit cages can be used as foraging trays. We fill the trays with wood chips or other types of bedding scattered with crushed maize, rice, or raisins, and attach them to the underside of the cage floors with bungie cords, thereby providing the animals with hours of searching activity. .. A spark of compassion in any one person towards the animals can be fanned into flames of empathy with the right encouragement, without destroying the primary research goals. In my experience [as attending veterinarian] it is utterly impossible, however, to make an uncaring person caring. Such people are not suited for this line of work (p. 35). .. There should be no sharp demarcation between 'good guys' and 'bad guys.' All employees, to some extent must share the work. Nonhuman primates are quick to forget, or perhaps forgive, the momentary fear or resentment they feel towards a human being who has just subjected them to an unpleasant experience if a strong bond of trust already exists with that person (p. 35). .. Of course, there is no such thing as a boring animal, rhesus or otherwise; only the conditions under which we keep them can be boring (p. 36)