light cycle is recommended with caregivers active during the "night" phase, when the area can be illuminated by red light.
Because cebids lack ischial callosities for sitting, they must "perch" using their feet rather than sit. Squirrel monkeys are likely to develop pressure sores on the dorsal surface at the base of the tail unless they are provided suitable perches and climbing structures, so it is important that appropriate materials be selected for the construction of perches (Abee 1985). Furthermore, pressure sores can occur in weakened animals that are unable to assume a proper perching posture. Squirrel monkeys are prone to hypothermia, especially if they are stressed, and materials that are poor thermal conductors or thermoneutral (such as wood and PVC pipe) are preferred over metal, particularly in environments in which the ambient temperature can fall below 24°C (75°F) (Abee 1989). At lower temperatures, the animals assume a "huddle" posture in which the back is arched and the tail is wrapped around the body. The same posture can be seen when the animals are sleeping, resting, or ill. At higher temperatures, squirrel monkeys "sprawl'' by straddling a perch or branch and allowing the limbs and tail to hang below. Squirrel monkey housing should be designed so that animals do not need to walk on wet abrasive floors, because animals are prone to develop contact dermatitis if forced to spend long periods in direct contact with urine-soaked concrete surfaces.
Most cebids maintain good health when fed commercial monkey chow that is specifically formulated for New World monkeys (i.e., is rated as high in protein—at least 25%—and contains vitamin D3) supplemented daily with fresh fruits and a vitamin-mineral supplement. Diets containing less protein and fat and more fiber might be preferable for some genera, such as Aotus, which have large ceca adapted for digestion of fruits and leaves. Furthermore, species prone to renal disease might benefit from reduced-protein diets. Vitamin supplements can be supplied by mixing them with fruit pieces or with a soft food base (such as yogurt, applesauce, infant cereal, or cooked grains). Some species (squirrel monkeys and capuchin monkeys) appear to need more folic acid than what is provided in commercial chow, particularly to support pregnancy and growth (Knapka and others 1995; Rasmussen and others 1982); consideration should be given to folic acid supplementation as necessary.
Howler monkeys are the most folivorous of the New World monkeys and are nutritionally difficult to maintain in captivity (Benton 1976; Shoemaker 1979, 1982). Strong tea instead of water has been suggested to provide the tannins that they normally obtain from leaves. Large amounts of leafy greens supplemented with Lactobacillus acidophilus are also recommended.
Aotus does well when given commercial diets with 5% or less fat and a high fiber content. Some taxa (such as A. griseimembra) might require supplemental