The Siberian Flying Squirrel Pteromys volans occurs only in Hokkaido. In Honshu, to the south, it is replaced by the Japanese Flying Squirrel P. momonga. If a prize is being handed out for the world's cutest creature, the Siberian flying squirrel is certainly in with a chance of winning.

These large-eyed tree-dwellers could come from a Disney film with their large eyes and, seemingly, expressive features. They get their name from their ability to escape predators by gliding from tree to tree by spreading out a thin flap of skin and stretching out all of their limbs.

Flying squirrels don't actually fly: they glide using a furry membrane or patagium between their front and rear legs. Using this membrane, squirrels have been known to glide over 100 meters, either to escape a predator or just reach another tree.

As dusk falls, they emerge from their dens and quickly climb up their tree trunk to reach the upper branches. They may feed there, or set off by gliding from tree to tree using the extensive patagial membrane that can be seen along their flanks. Stretched taut between outstretched limbs this membrane, combined with the flattened tail, gives them a large gliding surface, enabling them to travel considerable distances.

Their enormous eyes are a clear indication of their nocturnal habits. But on a clear winter's day, the whole forest seems to be reflected in the limpid mirrors of the domed surface of their eyes. Waiting at dusk for these creatures to emerge is a magical experience.