Subjects

We studied seventeen pairs (N = 34; n = 17 males, n = 17 females) of captive coppery titi monkeys (Callicebus cupreus) at the California Primate Research Center (Davis, CA) between 2013 and 2014. Both members of the pair served as subjects on different testing days. Mean (± SEM) age was 8.6 ± 1.5 years for males (range 2.3 – 23.2 years) and 7 ± 1.1 for females (range 2.1 – 15.4 years). One male was wild-caught and imported to the colony in 1990, but all other animals were born at the California National Primate Research Center.

All animals were housed with their partners and any dependent offspring in indoor cages measuring 1.2 m x 1.2 m x 1.8 m with four horizontal perches running the width of the cage in a staggered fashion. The housing rooms had a 12:12 light dark cycle with lights on between 0600 and 1800 and temperature was maintained at approximately 21° C. The monkeys’ diet included New World monkey chow, carrots, bananas, apples and rice cereal with water available ad libitum. The University of California Davis Institutional Animal Care and Use Committee approved all procedures described here.