Preliminary field observations on the marmoset,Callithrix humeralifer intermedius (Hershkovitz, 1977) at Dardanelos,Rio Aripuanã, Mato Grosso

The recently discoveredCallithrix humeralifer intermedius occurs between the Rios Roosevelt and Aripuanã in Brazil. This paper presents some preliminary observations ofC. h. intermedius in the wild from May to November 1978. They occupy dense primary forest, second growth and low white sand forest. Group size is between 4 and 13, the larger groups comprised of more than one adult pair. One group, watched for 160.5 hr, occupied a home range of 13.75 ha, during this period, travelling between 740 and 1,500 m during the day. Principal foods include small fruits, flowers, tree exudates and insects. Groups were observed with one pair of newborn infants during September and October, at the end of the dry season. Observations of social behaviour (including agonistic behaviour, grooming, tail coiling behaviour and scent marking), development of young, vocalizations and potential predators are described.