Higashi Kushiro Shell Mounds
Mounds of discarded clam and oyster shells and pottery fragments have been found along the Kushiro River, providing evidence of prehistoric human activity. It is believed that people settled in Kushiro around 7,000 years ago, after the last ice age ended and Hokkaido was separated from the Eurasian continent.
The Higashi Kushiro (East Kushiro) Shell Mounds consist of 11 separate mounds or middens, each up to 80 centimeters deep, arranged in a U-shape on a plateau about 15 meters above the Kushiro Wetlands. The shell mounds are on a settlement site that covers an area of 120 by 90 meters. They date back to a period some 6,000 years ago when people here began leading more settled lives. At that time the wetlands were part of the sea, and the site would have been on the shoreline.
With the establishment of permanent communities, people in the area relied on a combination of hunting, fishing and gathering for year-round sustenance. Pottery fragments in different styles ranging from the Jomon period (13,000–500 BCE) to the Satsumon period (600–1200 CE) have been found on the plateau near the shell mounds. Pottery developed significantly over the course of the Jomon period, and the variety of styles found here indicates that the area was settled for thousands of years.
Along with shells and pottery, archaeologists have found dolphin skulls arranged in radial patterns, as well as the remains of Steller’s sea lions and domestic dogs sprinkled with red iron oxide. These findings suggest that ceremonies may have been conducted at the site.
Full human skeletons were also unearthed from several pits at the Higashi Kushiro Shell Mounds. The arrangement of these skeletons in crouched positions in circular pits is consistent with the burial practices of the mid-Jomon period. A cross section of a real shell mound with shells is on display at the museum, along with pottery fragments and a replica of a Jomon burial pit.