Abstract # 1876 Event # 218:

Scheduled for Saturday, August 19, 2006 10:00 AM-10:15 AM: Session 21 (Regency East #3) Oral Presentation

The Neurobehavioral Development of Infant Rhesus Macaques (Macaca mulatta) Reared on Two Types of Inanimate Surrogate Mothers

A. M. Dettmer1, A. M. Ruggiero2, M. A. Novak1 and S. J. Suomi2
1Neuroscience and Behavior Program, University of Massachusetts, Amherst, MA 01003, USA, 2NIH/NICHD, Laboratory of Comparative Ethology, Poolesville, Maryland, USA
     Very few studies investigating the developmental outcomes of monkeys reared on inanimate surrogates have examined non-motorized mobile surrogates. In this study, six infant rhesus macaques (Macaca mulatta) were reared on mobile hanging surrogates (MS) and compared to six infants reared on standard stationary rocking surrogates (SS). Outcomes measured included neonatal reflexes, object concept permanence, novelty tests, and home cage and social behavior. Unless otherwise noted, t-tests were employed for analyses. MS animals received higher scores on visual orient to a stimulus at day 7 (p=.04), on auditory orient at day 21 (p=.01), and on spontaneous crawl at day 30 (p=.01). On the day 37 novelty test SS infants had higher frequencies of passive behavior than MS infants across the entire session (p=.003). No differences were observed for the day 75 novelty test. During object permanence testing, repeated measures ANOVA revealed that MS infants reached criterion at an earlier age than SS infants on the first stage, plain reach, only (p=.04). During months 6-8, MS infants spent significantly less time on their surrogates (p=.021) and more time exploring the far areas of the home cage (p=.003) than SS infants. In the first few months of life, SS infants spent more time in non-social play than MS infants (p=.04). These results suggest that a mobile surrogate may encourage faster development of gross motor skills and exploration in infant rhesus monkeys.