Bloomsmith, M. A., Truelove, M. A., Cowan‐Brown, J. et al. 2018. Comparing abnormal and fear-related behaviour under two nursery rearing conditions for infant rhesus macaques. American Journal of Primatology 80(S1), 35 (40th Meeting of the American Society of Primatologists Scientific Program, Abstract #95).

Two nursery rearing strategies for infant rhesus macaques (Macaca mulatta) were compared to measure effects on abnormal and fear‐related behavior. Changes made from the standard nursery‐rearing procedures (SN) included earlier exposure to peers, frequent peer‐group play sessions, the use of semi‐mobile artificial surrogates, and rotational pairing in the alternative nursery (AN). A variety of abnormal behaviors and fear‐related behavior was recorded using one‐zero sampling three to five times weekly, until subjects were about one‐year old. Thirty‐nine percent of the infants (N = 56) developed at least one type of abnormal behavior by 6 months old, and this rose to 55.4% by one year of age. The AN had a lower percentage of individuals with abnormal behavior at one year of age (12.5%, 1/8 animals), compared with 62.5% (30/48 animals) in the SN (Fisher's Exact Test, p =.017). Self‐oral behavior was seen in 88.7% (n = 53) of the subjects, with no difference in prevalence between nurseries. Fear‐related behavior was observed in 17.9% of the infants and did not vary between the nurseries. This analysis provides evidence that nursery‐rearing procedures can be important in preventing or reducing the expression of some abnormal behavioral patterns in young rhesus macaques, although perhaps not in fear‐related behavior. New practices evaluated in the published literature are being effectively applied to improve the welfare of nursery‐reared infant macaques.