Environmental enhancement for laboratory-housed squirrel monkeys: Fifteen-year retrospective analysis of procedures (1995)

Ricker, R. B., Williams, L. E., Brady, A. G. et al.

Abstract

The squirrel monkeys are housed in runs that allow them to travel from one cage to another. This allows for large (40 to 60 monkeys) multi-male, multi-female groups similar to those found in the wild. Each run is covered with dry deck flooring, which minimizes hand and food abrasions and provides a dry substrate for food foraging. During the summer when babies are born, the mats are replaced with 4 in of pine shavings. These shavings provide soft landing for falling infants and have decreased the incidence of infant head trauma. Two types of perching material were tried: polyvinyl chloride (PVC) and hemp (rope). The PVC was preferred by the animals and was set up in multiple levels, allowing use of vertical as well as horizontal space. Cut pieces of PVC pipe (12 in diameter) were hung in each run as a hide box, allowing eye contact to be broken between disputing animals. This decreased fight wounds by 60%. Infant toys were provided in each special group with little or no effect. However, they seemed to reduce stereotyped behavior in singly housed animals. Swings and plastic chains have all been added to successfully increase activity of group-housed squirrel monkeys. The lighting for the cage area is controlled by an automatic timer that tracks the times for sunrise and sunset. ... The addition of vegetables to the diet has been associated with increased infant birth weight. These few, relatively inexpensive ideas have reduced morbidity and increased reproduction in our squirrel monkey colony.