Enrichment device use by baboons during long-term vs (2000)

Hienz, R. D., Pyle, D. A., Frey, J. J. et al.

Abstract

Four of the six baboons increased their [cherry] log use over the exposure period [104 days], while the remaining two baboons decreased their interactions with their logs over this period. ...When the logs were available only every other day, or every fourth day, log use was considerably enhanced on those days. When the logs were withheld longer, log use declined to the same level of use observed when the logs were continuously available. These results suggest that leaving enrichment devices out of a monkey's cage for extended periods would not be beneficial for generating greater use.