Woelffer, S., Ace, L., Sullivan, J. et al., 2018. Enhanced physical environment in single-housed macaques: A long-term usage profile of cage extensions. American Journal of Primatology 80(S1), 19-20 (40th Meeting of the American Society of Primatologists Scientific Program, Abstract #25).

Social housing is always preferred in the research environment; however, single housing is sometimes necessitated by scientific objectives or social incompatibility. In these cases, other environmental enhancements are developed to provide indirect social interactions. We developed a novel cage extension that replaces the front of a standard cage to allow animals an enhanced visual perspective into the housing room and to provide additional space. To assess the effectiveness of the extension, we measured the amount of time that monkeys spent in the cage extension relative to the rest of the cage. We measured usage for one month following deployment and returned six months later to evaluate sustained use. Usage was evaluated using three strategies: Daily AM/PM location scan samples by animal research technicians; leading‐minute direct observation by behavioral staff, and remote video recording with no human present. We followed twelve animals with cage extensions. Over the first month animals spent over 80% of the observed time in the cage extensions. At the 6‐month follow‐up the animals spent 70% of their time in the extension; however, only five of the original animals remained in the room. Our findings show that the animals spent a large proportion of the time sampled in the cage extension and that this was maintained over time, thus suggesting that the use of extensions serve to promote non‐contact social interaction.