GB No. 2(17)/95
It is the beginning of August, a warm, windless night in the old beech forest. As the darkness grows deeper and deeper, the forest becomes more mysterious. All around you can hear the whispers, peeps, cheeps, and quarrels of the last birds. In this sleepy atmosphere, which does not seem unfriendly even for townspeople, uncommon sounds start to reverberate. First they are rare, then more frequent; some of them quiet, others loud; some short and importunate, others plaintive: krii, aii, uii... What animal has such a curious voice? In the strong light of a flashlight we can see an agile animal running high in the canopy. It is slightly smaller than a squirrel and has grey fur and a downy tail. This mysterious creature is the fat dormouse (Myoxus glis) -- a rodent from the family Gliridae. Fat dormice are very inquistive. So, we can see them at the moment when they sit down on a branch of the tree to have a look at the two-footed intruders. Even strong light does not frighten these animals. Big, shiny eyes attract our attention. They also have big, actively moving ears. If we watch them more carefully, we can see that the fur of the belly is light but the colour of the back is grey.
Generally, the fat dormouse has a season of "active life" (from November till April) and a season of "inactive life" called hibernation (from May to October). During the winter, when it is difficult to find something to eat, they hibernate. They lie curled up in their underground shelters. Their body temperature, which normally in summer is about 36oC , is reduced and maintained at the level of the surrounding temperature. During hibernation, metabolic demands are reduced to the minimal level for survival (for instance, oxygen cosumption, breathing rate, and heart and general circulation rate are reduced). Hibernation is a way of surviving cold winters when favourable food is not available. In the spring, after coming out of hibernation, fat dormice go to other type of shelters: treeholes, birdnests, etc. During the day they are hidden, emerging afer twilight to look for food. Their diet consists of seeds, buds, and the fruits of trees. To supplement their diet they eat animal food: insects, snails, eggs, and young birds. The young are born naked and clumsy. Each weighs about 1 -2 g. The female brings them up alone. Young fat dormice grow rapidly, and can be seen climbing high in the trees by September.
Fat dormice spend most of the night high in the canopy. They are very good acrobats. They can climb thick tree-trunks as well as slender twigs, and jump deftly from one branch to another.
Fat dormice prefer mixed and all-deciduous forests with thick, diversfied lower layers. In such habitats they can find both food and shelter (hollows in trees, crevices in trunks, etc.). Most of our managed forests, usually pine monocultures (Pinus silvestris), are unsuitable for fat dormice.
Cutting down huge areas of mixed and deciduous forests and even thinning of all-deciduous forests (mainly beech forests) during their natural regeneration are causing the extinction of fat dormice in many places in Poland. The fat dormouse is protected by law in our country, but that is not enough to ensure its survival. If we want to prevent its extinction, we have to preserve the habitat which fat dormice need to live.