SHORT COMMUNICATION

,Geophagy in Moustached Tamarins, Saguinus mystax (Platyrrhini: Callitrichidae), at the Río Blanco, Peruvian Amazonia

ECKHARD W. HEYMANN
Deutsches Primatenzentrum (German Primate Center)

and GERALD HARTMANN University of Göttingen

ABSTRACT. During a field study at the Rio Blanco in northeastern Peru between June and September 1990, moustached tamarins (Saguinus mystax) were observed to feed on soil material on three different occasions. Soil was taken directly from bare spots of surface soil (two observations) and from the broken mound of leaf-cutting ants (Alta sp.; one observation). Exposed surface soil is rare throughout the study area. Geochemical analyses of the soils that were consumed showed elevated concentrations of several elements in the ant mound sample compared to the other two soil samples. The most likely hypothesis for the function of soil feeding in moustached tamarins is that it serves in mineral supplementation.

Key Words: Saguinus mystax; Moustached tamarin; Geophagy; Geochemical analysis.

INTRODUCTION

Geophagy, the consumption of soil, has been reported for several primate species (e.g. DAVIES & BAILLIE, 1988; GANZHORN, 1987; HIRABUKI & IZAWA, 1990; HLADIK, 1977; MAHANEY et al., 1990; OATES, 1978). Four principal functions have been attributed to this habit in primates: (1) absorption of plant toxins (e.g. HLADIK, 1977; OATES, 1978); (2) adjustment of pH in the stomach (e.g. OATES, 1978); (3) mineral supplementation (e.g. DAVIES & BAILLIE, 1988; HIRABUKI & IZAWA, 1990); and (4) tactile sensation in the mouth (HLADIK & GUEGUEN, 1974). Function may vary from species to species and, as DAVIES and BAILLIE (1988) point out, within one species it may serve different functions at different times. Apparently, at least functions (1) and (2) are related to the fact that the diets of all primates for which geophagy has been documented so far regularly includes foliage, therefore generating the need for detoxification and pH-adjustment. In contrast to this, the present paper reports on geophagy in the moustached tamarin, Saguinus mystax, whose diet does not include leavy material, but is entirely based on fruits, arthropods, small vertebrates, exudates, and nectar. It is the first documented case of geophagy in a callitrichid monkey.