Using porches to decrease feces painting in rhesus macaques (macaca mulatta)

The goal of this project was to evaluate the efficacy of a porch in decreasing feces painting in captive rhesus macaques. The porch is a small extension that is hung on the outside of a monkey's primary home cage. Porches provide many potential benefits to indoor-housed macaques, including opportunities to perch above the ground, additional space, and increased field of view. Rates of feces painting, an abnormal behavior in which the animal smears or rubs feces on a surface, were compared in 3 situations: with porch enrichment, with 'smear board' enrichment (a foraging device commonly used to decrease feces painting), and without either enrichment item. Feces painting was evaluated daily by using a 5-point scale that ranged from 0, no feces present, to 4, multiple large areas of feces. We found that subjects received significantly lower feces painting scores when given porch enrichment or smear board enrichment compared with baseline. Furthermore, subjects received significantly lower feces painting scores with porch enrichment than smear board enrichment. These results demonstrate that the porch is an effective tool to decrease feces painting in captive macaques.