Saguinus niger popularly known as Sauim, is a Brazilian North primate. Sympathetic chain investigation would support traumatic and/or cancer diagnosis which are little described in wild animals. The aim of this study was to describe the morphology and distribution of sympathetic chain in order to supply knowledge for neurocomparative research. Three female young animals that came death by natural causes were investigated. Animals were fixed in formaldehyde 10% and dissected along the sympathetic chain in neck, thorax and abdomen. Cranial cervical ganglion was located at the level of carotid bifurcation, related to carotid internal artery. In neck basis the vagosympathetic trunk divides into the sympathetic trunk and the parasympathetic vagal nerve. Sympathetic trunk ran in dorsal position and originated the stellate ganglia, formed by the fusion of caudal cervical and first thoracic ganglia. Vagal trunk laid ventrally to heart and formed the cardiac plexus. In abdomen, on the right side, were found the celiac ganglion and cranial mesenteric ganglion; in the left side these ganglia were fusioned into the celiac-mesenteric ganglion displaced closely to the celiac artery. In both sides, the caudal mesenteric ganglion was located near to the caudal mesenteric artery.

As a member of the Mustelidae family, E. barbara has characteristics common to the family, including a slender body with a long tail (twothirds the size of its body) (