Home range size and pattern of range use in common marmoset groups, Callithrix jacchus (Linnaeus) (Primates, Callitrichidae)

The influence of abundance and distribution of fruits and gums resources in home range size and pattern of range use were investigated in Callithrix jacchus. From October 1996 to January 1998 two groups (QT and PB) that lived in a National Forest/IBAMA-RN in northeastern Brazil (6º5'S, 35º12'W), were observed once a week by instantaneous scan sampling. The frequency of quadrant's visit in the home range was recorded at five minute intervals. Trees used for feeding on fruits and/or gum by the study groups were marked with flagging tape and numbered. Samples of the food items were collected for identification. Data on the temporal variation in fruits abundance was based on the monthly phenological observations of the marked trees. Study groups showed small home range size (QT: 2.4 ha and PB: 0.7 ha). No significant differences in home range size between dry and wet months were found, but groups showed a tendency to broadened the range use in the wet months. This revealed a behavioral strategy which marmosets exploited more gums face to decreased in fruits abundance. The abundance and distribution in clusters of fruits and gums resources influenced the pattern of range use and home range size