In arctic zones, the pre-modern people’s bodies have often been mummified by the combined effects of low temperature and humidity [1-3]. Those mummified remains have been discovered during archaeological investigation; and the study of them becomes important means to reveal the physical traits of the arctic peoples of the past times. So far, many groups conducted investigations on the permafrost mummies of arctic or subarctic zones worldwide [1-6].

In West Siberia too, anthropologists researched arctic or subarctic permafrost area of Yamalo-Nenets Autonomous Okrug (Fig. 1A, B). Particularly, medieval graves of Siberian native peoples were investigated in large quantities at the arctic cemetery [3, 5]. Inside the graves of the area, the dead bodies are found in a form surrounded by birch bark, which is called a mummy cocoon [5]. These graves can be valuable materials because the cultural relics used at the time could be obtained; and bioanthropological studies could be conducted on the well-preserved mummies found therein [3, 5].

Figure 1. The cemetery of the Zeleny Yar (Z-Y) site in Yamalo-Nenets Autonomous Okrug. Yellow shadow box in (A) is magnified as (B). (C) The burial #79 of Z-Y cemetery. Bronze plate and strips placed upon the birchbark cocoon: 1, a rectangular plate above the head part. Long bronze strips at 2, chin and neck; 3, the lower part of chest; 4 and 5, abdominal region; 6, pelvic area; 7 and 8, lower extremities; 9 and 10, the foot.

Nevertheless, its anthropological full extent is not well known except to local scholars. Especially, relatively little is revealed to the outside world about the biological aspects of the mummies discovered in the medieval graves. More detailed studies are required on the mummy cocoons excavated in the arctic cemeteries of the West Siberia.

Our research team conducted excavations on the graves of the Zeleny Yar (Z-Y) site (66°19’4.54”С; 67°21’13.54”В) [5], a flood plain island cemetery near Salekhard City, Yamalo-Nenets Autonomous Okrug (Fig. 1A, B). From 2013 to 2017, 47 burials were discovered at the place. The construction date of cemetery was approximately estimated to be 12th to 13th century by archaeologists. Among the burials in the cemetery, the data of mummy cocoon was presented for the grave #53 [5]. The excavations of the burial ground are not conducted any more. However, there are still mummies of the cemetery that are not reported yet. This report is thus designed to introduce the findings of mummy cocoon #79 of the Z-Y cemetery.

The burial #79 was present at a depth of –0.47/–0.54 m from the conditional zero. The outline of the burial #79 was an oval-trapezoidal shape. The length of the burial is 210 cm; widths are 45 cm (southern part) and 29 cm (northern part) respectively (Fig. 1C). We found that the burial #79 was cocooned by birch barks. Upon the cocoon, we identified multiple bronze plate and strips (Fig. 1C). A rectangular plate was found above the head part of mummy; and there were long bronze strips in the mummy’s trunk part (Fig. 1C). Recognizing the need for scientific investigation of mummy cocoon, en bloc cutting of soil around #79 was conducted with a hacksaw. The extracted mummy cocoon was then carried out to Labytnangsko District Clinical Hospital (Yamalo-Nenets Autonomous District), for taking computed tomography (CT) images.

In CT radiological data, we re-confirmed the presence of ten bronze plate and strips (Fig. 2A). We also identified one more bronze strip hidden inside the fabric, at the left periphery of the mummy cocoon (Fig. 2A). For the mummy of the cocoon, we observed multiple internal organs: for instances, brain and eyeball inside the skull (Fig. 2B–D). The mummified brain was atrophied back to the dorsal side of cranial cavity, possibly caused by the long-term action of gravitational force and dehydration (Fig. 2C). In the upper extremities, trunk, and lower extremities, the bones were covered by very thin skin and soft tissues (Fig. 2E, F).

Figure 2. Radiological images of #79 burial of Zeleny Yar cemetery. (A) The bronze plate and strips (1–11) on radiological image. Numbers represent the bronze plate and strips described in results of this paper. (B) Radiography of mummy head. Lateral view. 1 is for bronze plate covering the face. (C) Mummy head axial view. Br and Ey remained inside the skull. (D) Lower part of mummy head. Br remained in the cerebellar fossa. Yellow arrow indicates the bronze plate covering mummy face. (E) and (F) The skeletons of lower extremity. S, skull; Br, brain; Ey, eyeball; Fm, femur; Tb, tibia; Fl, fibula.

The cocoon #79 has been curated in Institute of the problems of Northern development of Tyumen Scientific Center, Siberian Branch of Russian Academy of Science, Russia. The mummy cocoon was investigated in the lab by anthropologists while performing scientific records. Around the mummy cocoon #79, under the bronze plate or strips, the fragments of woven cloth could be found (Fig. 3A). Fur products, possibly made of reindeer skins, covered mummy face and trunk found underneath the bronze plate or strips (Fig. 3B). Mummy’s face and body could be exposed after the removal of the fur (Fig. 3C). Around right mastoid process, glass and bronze beads were found. At the shoulder girdle, there was a fragment of leather strap. Copper bracelets were identified around the right forearm (Fig. 3C). An iron knife was also seen at the right side of pelvic bone. Like CT images, the mummy’s skin, muscle remnants, and skeletons were preserved (Fig. 3C). The sex of the buried person was estimated to be a male by external sexual characteristics during the investigation. His age was likely to be 20 to 35 years old by dental attrition.

Figure 3. A mummy of #79 burial of Zeleny Yar cemetery. (A) Fur products (white asterisk) covering the mummy face. (B) Mummy’s face (red asterisk) under the fur product. (C) The mummy’s face and upper body were preserved. Note copper bracelets (yellow arrows) around the forearms.

This study was exempted from Institutional Review Board (IRB) review by Seoul National University Hospital (IRB No. 2017-001).

The arctic region is a hard place for any people to live on. Nevertheless, native people lived there even before Siberia was incorporated into European civilization, successfully overcoming harsh environment. In this study, we describe in detail the arctic mummy of Yamalo-Nenets Autonomous Okrug where indigenous peoples lived in various forms of lifestyle [7]. These arctic tribes include Khanti and Nenets. In medieval times, they lived as fishermen, hunters, and reindeer herders of the Arctic Circle [3]. However, as for the specific circumstances of their lives, it is not easy to understand completely due to the lack of documented records so far.

Arctic or subarctic regions are permafrost places where well-preserved mummies could be often found [3, 5]. Scientific investigations on the mummies in Greenland, Alaska, and Canada thus can provide rich data about the life of arctic native peoples [1, 4, 6]. Meanwhile, as for West Siberia, though not a small part of its the aboriginal peoples lived on the territory in the arctic or subarctic regions for a long time before immigration of Europeans, anthropological data therefrom are still not sufficiently reported to the outside world. In this sense, anthropological data obtained in this study is very significant to anthropologists.

The cemetery subject to the current report is likely the graves of Khanti and Nenets. The excavation of the cemetery began since 1999, and investigation continues so far [3, 5, 8, 9]. As the cemetery was built in 12th and 13th century, our study can be an anthropological survey of the West Siberian arctic people of the same period. Several studies of the mummy therefrom yielded invaluable anthropological data about them [3, 5, 9-11]. For instance, as for burial #53, multiple layers of birch bark and fur veil wrapped the dead body. Well-preserved human remains, bronze or iron items were found around the #53 body’s head, thorax, abdomen, and thighs [5]. However, the report of detailed information regarding the mummy itself is still rare.

In this study, we report the details of #79 burial among others in the cemetery, with more emphasis on mummy's anthropological aspects. Repeated freezing or evaporation under low temperature, low humidity, and high-speed wind protected the human bodies from decomposition or putrefaction [1-3, 12]. The mummification of this cemetery was not artificially induced, but naturally caused under permafrost conditions. This naturally formed mummy cases enable us to obtain scientific data concerning arctic peoples of West Siberia, which is difficult to be obtained by other historical methods.

In this study, we conducted CT analysis to conjecture the inside condition of #79 mummy cocoon before the investigation began. On CT images of cocoon, human remains along with other cultural artifacts could be identified. The internal organs of buried individual like brain and eyeball could be identified on radiographic images. As for cultural relics, traces of textile, fur products, bronze plates, bracelets, and iron knife etc. were found around or inside the mummy cocoon. Taken together, we can successfully attain data helpful to reveal the detailed pattern of indigenous arctic mummy of medieval times though more anthropological reports must be conducted more on the similar cases in West Siberia.

Conceptualization: SMS, DHS. Archaeological Excavation: SMS, AVG, EOS. Anthropological data acquisition and analysis: SMS, JHH, HL, DHS. Radiological data analysis: SMS, DHS. Drafting and revision of the manuscript: SMS, DHS. Approval of the final version of the manuscript: all authors.

No potential conflict of interest relevant to this article was reported.