Abney, D. M., Harding, K., Toscano, J. et al. 2014. Successful social housing of mature male cynomolgus macaques in mixed sex rooms. American Association for Laboratory Animal Science [AALAS] Meeting Official Program, 567. (Abstract #P70).

We are committed to ensuring all our animals have the highest level of care and welfare. To this end, our social housing program includes placing all animals in pairs or groups. We have a rate of almost 100% success social housing juvenile and sub-adult animals, as well as adult females. Social housing of sexually mature males can be a challenge. Some publications suggest that it is not advisable to attempt adult male introductions in mixed sex rooms of rhesus macaques (Macaca mulatta). However, separating animals into single sex rooms introduces a potential scientific confound as well as operational inefficiencies, and to our knowledge this data has not been published for cynomolgus macaques (Macaca fascicularis). Data was collected from 2 sites that are actively social housing mature males. For the purposes of data collection, sexually mature males were defined as 5 y of age and 5 kg or greater. As is common in toxicology research, all animals had a narrowly defined weight range. A pair/group was considered successful if they had maintained compatibility for a minimum of 2 wk. All social housing attempts were made in rooms with females present and visible to the males. A total of 21 rooms were analyzed, and 81% of the rooms surveyed had success in pairing the majority of males in the room. Fifteen rooms had a success rate of 75% to 100% (median 92%) with more than 280 male animals being socially housed. This data shows that mature males can be successfully socially housed in rooms with females. The ability to compatibly socially house mature males in mix sex rooms does not compromise welfare and allows for greater flexibility of vivarium space usage.