The distribution of elastic fibers in the filiform papillae of 1, 2, 3, 4 and 5 week-old and 6 month-old Suncus (Suncus murinus; insectivora) was examined by both Weigert's resorcin-fuchsin method and ultrastructural means. In the adult Suncus (6 months old), elastic fibers in the connective tissue core of the papillae were aligned perpendicularly to the epithelial surface and formed a palisade-like structure which encircled the margin of each connective tissue core. This characteristic structure was restricted to the filiform papillae in the anterior half of the lingual dorsum. In the filiform papillae of the posterior half, elastic fibers were markedly reduced and the palisade-like structure was not present. This characteristic pattern of elastic fiber distribution was established by 3 weeks of age. These observations reveal a characteristic structure consisting of elastic fibers in the connective tissue core of the filiform papillae and the regional distribution of this structure in the tongue. This suggests that the function of the structure in the connective tissue core is to protect against mechanical stress in mastication. The regional distribution of this structure may reflect the difference of mechanical strength between the anterior and posterior of the tongue caused by tongue movement during mastication.