CIRCADIAN AND ULTRADIAN PERIODICITIES OF GROOMING BEHAVIOR IN FAMILY GROUPS OF COMMON MARMOSETS (CALLITHRIX-JACCHUS) IN CAPTIVITY

Three families' groups of common marmosets were observed to describe t he characteristics of their grooming rhythmicity, as the duration of t he episodes of self- and social grooming made and received by the anim als, in captivity under natural environmental conditions. Data were co llected by focal animal sampling, at 20 min hourly intervals during 16 non-consecutive days, from January to March in 1994 (sunrise: 05:24 h +/- 2 min; sunset: 17:34 h +/- 1 min). Time series were obtained for each individual and for each family through hourly duration of groomin g, Family time serie was obtained through the mean of its individuals time series. Spectral analysis revealed statistically significant circ adian rhythms for all families and individuals, Ultradian components w ere detected in 50% of the families and in 46.7% of the animals. Acrop hases of self- and social grooming calculated by Single Cosinor Look p lace between 9:21 h and 10:39 h, for the families. Far individuals sel f- and social grooming made and received, acrophases occurred from 8:3 5 h to 12:43 h. The confidence limits of acrophases did not show diffe rences between the families and the individuals within the families, i rrespective of their sex, age and reproductive condition, suggesting t hat this behavior has a stronger temporal marking. Grooming has circad ian and ultradian components of rhythmicity in captive families' group s of common marmosets, under natural environmental conditions. Since o nly some animals showed the ultradian component, it may be consequence of social or environmental masking, or yet phenotypic plasticity of t emporal genotype. Further studies are needed to test these possibiliti es.