Eurasian Forest Dormouse

The Eurasian forest dormouse is an arboreal rodent with a soft gray-brown coat, pale underside, conspicuous dark mask through the eye, rounded ears, and a well-furred tail. Its masked face separates it from most mice, while the bushy tail distinguishes it from voles and field mice. It belongs to the dormouse family Gliridae and is distributed from eastern Europe and the Balkans into western and Central Asia. The opened account does not give measurements reliable enough for a concise species-wide statistic. (Wikipedia, forest dormouse account)

Forest dormice live in wooded habitats, including mountain forests, and use above-ground nests and natural cavities. After emerging from winter hibernation they eat small invertebrates, young birds, buds, shoots, and other green plant parts; later in the year fruit, nuts, and seeds become more important. This seasonal shift helps build reserves before the next dormant period. The Mammal Diversity Database confirms Mongolia, but the opened sources do not identify a named Mongolian forest or document local timing, so no narrower viewing advice is offered. (Wikipedia, forest dormouse account; Mammal Diversity Database, Mongolia country list)