Interspecific variation of scent-marking behaviour in wild tamarins, Saguinus mystax and Saguinus fuscicollis

The scent-marking behaviour of sympatric moustached, Saguinus mystax, and saddle-back tamarins, Saguinus fuscicollis, was compared in order to explore interspecific differences and potential sources of variation. The author examined basic patterns of scent marking (types, intensity, complexity), substrate use (type, orientation, height), and social patterning of scent marking in three groups of S. mystax and one group of S. fuscicollis at the Estación Biológica Quebrada Blanco, Peruvian Amazonia. S. mystax and S. fuscicollis differed significantly in the relative frequency of different types, and in the intensity and complexity of scent marking. Only S. fuscicollis showed allomarking. They also differed significantly in the type, orientation and height of substrates used for scent marking which corresponded to general differences in substrate use. In S. fuscicollis, but very rarely in S. mystax, two or more group members marked the same site sequentially or simultaneously. 'Collective scent marking', i.e. simultaneous scent marking by most or all group members, occurred only in S. fuscicollis. Since both tamarin species live sympatrically in mixed-species groups, ecological factors are unlikely to account for the differences found in scent-marking behaviour (except for differences in substrate use). They probably relate to as yet unknown differences in social and reproductive strategies of the two species.