Photo/IllutrationA Japanese dormouse in hibernation (Provided by the Keep Yamane Museum)

HOKUTO, Yamanashi Prefecture--It’s bedtime for a Japanese dormouse named Nomu Nomu, who is sleeping peacefully curled up in a ball at the Keep Yamane Museum here.

Under a red light, visitors have the rare chance to observe the rodent hibernating in the cold room shielded by a blackened curtain.

The Japanese dormouse, called yamane, is a near-threatened species protected as a national natural treasure.

“Nomu Nomu is smaller than we expected, but it is very cute,” said Yoshimi Hyuga, 76, and Ryuko Hyuga, 73, a couple visiting for the first time from Kofu.

Among Japanese dormice captured in late autumn, the museum chooses those that are small and will most likely struggle to survive in their natural environment. The selected ones sleep through the winter at the museum.

Yamane decrease their metabolism in hibernation. Still, their weight drops to two-thirds of normal after their winter slumber.

Nomu Nomu's body temperature has fallen to around zero, almost the same as the room temperature.

“Yamane survive in periods of no food through hibernation. In the Kiyosato Highland outside the museum, they tend to be dormant for long periods from November to April,” said Manami Iwabuchi, 39, a yamane caretaker.

A hibernating Nomu Nomu can be seen until around March. Open hours are from 10 a.m. to 4 p.m., with the museum closed Tuesdays, Wednesdays and Thursdays. Admission for elementary school students and older is 320 yen ($3).