Pictures of them playing are unusual as they are shy animals and nocturnal
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.
Two squirrels in particular appear to be giving their cutest poses for the camera with one particularly adorable image showing a squirrel peering out from a nest hole.
Photographer Masatsugu Ohashi captured these images of the tiny animals, also known as Russian flying squirrels, on the Japanese island of Hokkaido.
The reclusive creatures are shy, nocturnal animals and in winter may sleep continuously for several days. Seldom seen, they like to inhabit trees in which woodpeckers have left holes suitable for comfy nests.
Masatsugu explains: 'The squirrels make this tree a nest every year when it is winter. Five of them live communally in the cold season.
'It is early morning and in the evening they become active. They are almost always in the nest so chances of photographing them in the daytime are difficult.'
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.
The squirrels prefer tall pine, cedar or spruce trees where they can use abandoned woodpecker holes as nests rather than making one themselves.