This squirrel is a subspecies of the Siberian Flying Squirrell (Pteromys volans orii). Ezo was the name of the Island of Hokkaido until 1969. The Ainu are the original inhabitants of Hokkaido before the Japanese. More on the Ainu by the inactivist on: Ainu Songs and Land of the She-Bear Women

The Ezo flying squirrel was known to the Ainu as At-kamui or “The Divine Prolific”. Considered the Divine Spirit of Children by the Ainu and regarded as a bird, since it could fly. Childless couple would ritually eat the squirrel to induce fecundity.

By Tokumi – Own work, Copyrighted free use, https://commons.wikimedia.org/w/index.php?curid=97984890

By T-konno – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=114988383

Just for fun, two more critters of the Ainu Pantheon:

Akkorokamui (Japanese: アッコロカムイ, Ainu: At-kor-kamuy) the Tentacle Spirit is a giant octopus that lives in Uchiura Bay.

Amemasu (雨鱒アメマス) or Ō-amemasu (大アメマス)or Rain Trouts are giant fish-like creatures that enjoy capsizing boats or shift-shape into attractive women who lure unwise men to their demise. The very large Anemasu cause earthquakes, like the one that lives in Lake Kussharo, a volcano caldera in Akan National Park, eastern Hokkaidō. The island in the middle is a stratovolcano in the making and the suspected abode of the Anemasu.

A tourist industry around the Anemasu is developing locally following the Loch Ness Monster model. The magical being has a new name: Kussie (or Kusshī) and a new look:

More Posts in the inactivist on the Ainu: Ainu Songs & Land of the She-Bear Women

By Soica2001 (talk) – Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=10875461

By 663highland – Own work, CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=23474609