DIURNAL-VARIATION AND DISTRIBUTION OF GROOMING BEHAVIOR IN CAPTIVE COMMON MARMOSET FAMILIES (CALLITHRIX-JACCHUS)

Grooming is an important social activity among primates. In an investi gation of its diurnal distribution, all grooming episodes (self- and a llo-) were recorded in three families of captive common marmosets (Cal lithrix jacchus) kept under natural environmental conditions at hourly intervals for periods of 20 min from 05:00 to 18:00 h, for three cons ecutive days a week for four weeks. The three families were composed o f a reproductive pair and their offspring, with 8, 8 and 7 individuals , respectively. No significant variations were detected within familie s in terms of days or weeks. However, one family did perform more groo ming than the others. The frequency of grooming episodes per hour/per family was higher during the period from 08:00-12:00 h, with acrophase s narrowly distributed near 10:00 h, (Family 1 = 10:32 +/- 00:33 h; Fa mily 2 = 10:11 +/- 00:13 h; Family 3 = 09:45 +/- 00:14 h) and lower fr equencies were observed at the beginning and end of the active period. The differences between families are probably related to the social d ynamics of the individual groups and not to their size.