[Returning marmots hibernation in spring. Marmottes à la sortie d'hibernation].

Résumé

Spring is the most extremal period for marmots. At that time unfavourable climate conditions often interrupt their upground activity. Sometimes these periods may be long enough. There are some suppositions in literature about returning hibernation in spring. But it is very hard to get real data about hibernation. The aim of this work was to investigate the influence of starvation on marmots in spring after the beginning of their activity. The basis of experiment was the marmots farm. Marmots lived there in cages with wooden boxes. The boxes were fulled with hay. M. bobac and M. caudata were under the observations. The interruption on feeding at the end of March- first part of April didn't influence to the body temperature of adult animals which were breeding or ready to this process. They continued to support high and stable body temperature (36-38 des. C) even after two weeks of starvation. At the same time weak adults and young animals decreased their body temperature after some days of starvation. A number of days was different for every individual but usually it was about 1-4. Hibernation in spring wasn't so deep as in winter. Marmots often got up and more quickly reacted upon the changing of extremal conditions (touching, increasing air temperature and so on). Most part of animals became active in a few hours after putting food near their compartments. Body temperature grew to 36-38 deg. C after restoring of feeding. But it didn't become stable in weak and young marmots. If starvation restored again hibernation also restored. In our experiments the process of returning hibernation was observed till the beginning of May. Probably it could be continue longer but high air temperatures limted low border of body temperature in this case. That's why the experiments were stoped. Air temperature in burrow is low and constant, it hasn't such influence on the low border of marmots body temperature. The animals in nature evidently can return in hibernation for a longer period of time, till the begining of constantly favourable conditions. This mechanism plays great role in surviving of weak and young marmots. This process is very important for populations which dwell in extremal conditions.