rooms to complexes of small wire cages or even small single cages with a volume of 1 or 2 m3. For monitoring and protection from hypothermia, the smaller, mainly nocturnal forms are best kept indoors on reversed lighting schedules.
Prosimians rarely attack cage structures. Perhaps as a consequence of their ability to leap and move rapidly through thorny scrub in their natural habitat, they are less likely than other primates to be injured by wire. Wire cages provide extensive climbing surfaces for small prosimians. Prosimians make good use of shelves, ropes, or swings and do well with natural substrates—such as vines, bamboo, and branches—to climb on or jump among. With regular cleaning and replacement of cage furniture, wooden objects have not been implicated as natural-disease vectors. Attempts to keep and breed promising under conditions that maximized sanitation and lacked nest boxes or appropriate substrates for climbing and jumping affected reproduction and survival adversely. In fact, the effects of long-term housing under these conditions were not readily reversed when the animals were provided more suitable housing in which other members of their species thrived.
True lemurs (Lemur, Eulemur, and Varecia) do well in large outdoor enclosures. Some success has been reported in smaller runs with a minimum of 5 m3 (175 ft3) per animal. Indoor rooms may also be used, although lights must be kept on a timer or on a manual light cycle designed to simulate seasonal photoperiod changes to ensure breeding. Concrete flooring of either indoor or outdoor enclosures is contraindicated because animals have been killed by falls onto concrete surfaces. Heated shelters larger than 60 cm square (2 ft square) should be provided with resting and feeding shelves. Under severe weather conditions, lemurs might need to be secured in sheltered housing because some will not use heated shelters regularly otherwise. Lemur housing should be furnished with vertical and horizontal natural substrates, such as vines, bamboo, and branches. Weekly sanitation of PVC "branches" has been associated with anogenital micro-abscesses in Varecia. Natural substrates sanitized less frequently do not produce such problems.
Large forested enclosures are suitable for lemurids, and one enclosure can hold species of all lemurid genera, inasmuch as these species are not hostile or competitive toward each other. The use of electric fencing is effective when groups are socially stable, but animals rejected by their social group will escape over such fences. Sand or grass flooring in enclosures can be maintained if spot-cleaned and raked daily. The Duke Primate Center has found weekly sanitation of shelter-box interiors and monthly sanitation of the cage furniture, nest boxes, and windows to be effective in maintaining sanitation and providing essential species odors.
In contrast with true lemurs, Cheirogaleidae (mouse and dwarf lemurs) seldom jump more than a meter and are conveniently housed in cages containing family groups of pairs or trios of animals plus the season's juveniles. Cages as small as a 1.2-m cube (3.9-ft cube) appear to provide adequate space for such