Lee, G. H., Thom, J. P., Chu, K. L. et al. 2012. Comparing the relative benefits of grooming-contact and full-contact pairing for laboratory-housed adult female Macaca fascicularis. Applied Animal Behaviour Science 137(3-4), 157-165.

This study compares the benefits between the two housing types by video recording 14 pairs of adult female Macaca fascicularis in four sequential housing phases following an ABBA design: baseline grooming-contact, full contact shortly after introduction, 1-month-later full contact, and after reversion to grooming-contact. Prior to this study, pairs had been housed compatibly in GC. Twelve of the 14 long-term pairs transitioned successfully to full contact and data presented exclude the two failed pairs. Allogrooming increased significantly when pairs first switched from GC to FC (P = 0.018), but the effect did not last through 1-month-later FC phase suggesting that the initial improvement in affiliative behavior was a transitory novelty response that did not persist. Self-grooming significantly decreased between the first GC and first FC phases (P = 0.016), likely due to redirected allogrooming. Non-contact affiliative behavior towards partner or other conspecifics in the room did not differ, nor did agonism towards partner or others in the room. Occurrence of abnormal, tension, manipulation, miscellaneous active, and inactive behaviors did not differ significantly across housing phases. Proximity measurements indicated that pairs were significantly out of arm's reach more often in protected contact than when in full contact (P = 0.02). Proportion of time spent in physical contact significantly increased between the first GC and first FC phases (P = 0.002), but subsequently declined. For both FC phases, partners chose to spend about 50% of their time in the same cage. Few behavioral improvements were seen after pairs switched to full contact and no negative effects came of reversion to grooming contact. This study suggests that tactile contact provided through widely spaced bars (grooming-contact) is a viable alternative to full contact housing for adult female longtailed macaques. It provides a degree of social housing while allowing both partners choice and control, key concepts in contemporary animal welfare guidelines.