Identification of hairs of the wooly mammoth Mammuthus primigenius and wooly rhinoceros Coelodonta antiquitatis using scanning electron microscopy.

Abstract

Hair of the woolly mammoth Mammuthus primige� nius Blumenbach, 1799 has been studied for many years. Judging from the ancient rock paintings, figu� rines, and preserved hair fragments, as well as from the data of numerous paleontological researches, the mammoth hair was long (up to 1 m or even longer), thick, multitiered, and with topographical differ� ences. The hair coat of the woolly rhinoceros (WR) Coelodonta antiquitatis Blumenbach, 1799 was also thick and long. The wool of both species was three� tiered: the most numerous downy hairs, which formed a thick underhair, the long and sparse intermediate (or guard) hairs, and the sparsest overhair giving fluffiness to the wool. The hairs grew in the skin singly and had sebaceous glands (1, 2). Tens of the dead mammoth bodies were found in permafrost, and the mammoth hair microstructure was the subject of numerous studies (3-6). Only a few overhairs have the fragmented medulla consisting of meshes irregular in shape and with jagged edges; they are loosely arranged along the hair axis. The mam� moth hair cuticle, which is not annular because the scales do not fully encircle the shaft, is heavily damaged as a rule, and the free edges of the scales are broken. The WR remnants with soft tissues are much more rarely found in the permafrost than the mammoth remnants; therefore, the WR woolly coat has been much less studied. Until now, no fundamental differ� ences have been found in the hair structure between recent rhinoceros species and WR: as in the mam� moth, rhinoceros hairs are deprived of medulla, have a mosaic cuticle pattern and the true cylindrical shaft. All of the main hair structures are nonspecific; there� fore, it is impossible to determine even generic affilia� tion of wool (7). The lack of hair coat and subcutane� ous fatty tissue in recent rhinoceros, as well as the presence of numerous large and actively secreting apo� crine glands are believed to be related to specific ther� moregulation in these inhabitants of tropics (8). Under the conditions of the Ice Age, the heavy hair coat of WR contributed to their survival.