On the size of the Marmots (Marmota), their annual cycle and adaptations to the "short summer" [O razmerakh sourkov (Marmota), ikh godovom tsikle i adaptatsii k "korotkomou letou"].

Résumé

The difference in the body size and condilobasal length of the skull between the marmots of Eurasia and North America is hardly noticeable. Small and large species and subspecies are found on the both continents. No increase in the body size and condilobasal length are observed in the northern parts of the range and in the high mountains. The proportion of the duration of the surface activity and hibernation vary in different marmot species, the hibernation period is prolonged in the habitats with the "short summer". Various adaptations make it possible for the animals to live under the extreme conditions and reduced period of the surface activity.