Diurnal variation in scent marking behavior in captive male and female common marmosets, Callithrix jacchus

Chemical communication by scent-marking behavior in New World primates is u sed to prevent the access of potential competitors to a territory, to ident ify food resources and the reproductive condition of mates, among others. I n common marmosets, primates of the Callitrichidae family, this behavior al so occurs as olfactory identification of an individual or of the reproducti ve status of females. Despite this information, the diurnal variation and g ender differences in the profile of this behavior remain to be investigated . The aims of this study were to establish the diurnal profile of the distr ibution of this behavior and the influence of the sex of markers. We used 1 8 adult common marmosets, Callithrix jacchus, 10 males and 8 females from 6 family groups (6 fathers and 4 sons; 4 mothers and 4 daughters). The frequ ency of scent-marking behavior was recorded for each animal over a period o f 8 days, twice a week, for 4 weeks, starting when the animals left the nes t box (approximately at 05:00 a.m.) until the end of the photophase, at abo ut 05:00 p.m. A MANOVA test was performed to compare the frequency of scent -marking behavior at 2 hour intervals using pooled data for males and femal es. The results showed that significantly higher levels of scent-marking be havior occurred during the 03:00-05:00 p.m. interval compared to all other intervals. Lower values were recorded during the 11:00-13:00 interval and a n effect of the sex factor was also found, with the values being higher for females than for males, although a significant difference was recorded onl y for the 07:00-09:00 interval. Minimal values for males were recorded duri ng the 07:00-09:00 interval, whereas minimum values for females were record ed during the 11:00-13:00 interval. However, the highest values for both se xes continued to occur during the 15:00-17:00 interval. These results sugge st that scent marking behavior in common marmosets has a preferential incid ence at the end of the day and this might be occurring in association with feeding behavior. At this time these animals usually forage more to prepare for the night's fast. Since these animals can discriminate chemical clues as long as 24 hours after they have been left, the higher incidence of this behavior at this time probably will assure that the animals will localize feeding resources used on the preceding day. Significant elevation of scent marking behavior in females in relation to males was found only at 07:00-0 9:00 interval and seems to be associated with signalizing of reproductive s tatus, preferential access to foraging or both.