Inexpensive outdoor enclosure for Japanese macaques used in biobehavioral research

For studies of alcohol self-administration in a monkey social group, we effectively and humanely enclosed nine Japanese macaques (Macaca fuscata) in an ellipse 32 x 40m, with a 1 m high chain-link fence surmounted by a 3 m curtain of electrically conductive nylon net. High-voltage brief-pulse charges prevent climbing on the net. Materials for this fence cost less than $14.50 per running meter. Weeds and grass grew freely within the ellipse, and seven dead trees interconnected with ropes permitted climbing and swinging. An open, roofed gazebo provided sun and rain shelter, and its single wall blocked the prevailing wind. Mouth activated drinkometer spouts in the corral supplied solutions for voluntary alcohol self-administration. Automatic counters informed an observer of exact doses consumed by each subject. Another observer recorded the frequency of occurrence of various social behaviors. A small kennel run, roofed over with chain-link fencing, connected the corral with a paddock-like, partially heated building, to and from which the monkeys usually had free access. It contained three interconnected chain-link pens. A raceway opening from the pens incorporated a squeeze cage used for weighing animals, drawing blood samples, or administering medications. This unique facility promotes the psychological well-being of research primates, which is being mandated by federal law.