One of the important ecological features yellow gopher is summer and winter sleep, which lasts about eight to nine months a year, and it is peculiar to the whole area. It attracted the attention of many biologists and physiologists (Kashkarov and Lane Co-fencing, 1927 Kalabuhov, 1946 Bulls and Slonim, 1949, and others), in varying degrees, who described hibernation and explain this complex and interesting phenomenon. The complexity of it is above all in the fact that not all squirrels are equally and simultaneously respond to the changing environment, so not all look the same sleep soundly and in the same time frame. The first lie adult males and females proholostavshie, followed females participating in reproduction, and the last — immatures and profits. Wake up before all adult males, eight to ten days after the adult females and least in the last year gophers litter (Ismagilov, 1955, 1956). In southern and animals lie awake earlier than in the north.
Differences in the timing of awakening also depend on how early starts spring in the area. For example, the animals began to come out of the holes in Muyunkum: in 1953 — March 2, 1954-25, 1955-10, 1956-2, 1957-18, and in South Balkhash region: in 1953, 27 February 1954-20 March , 1955-21, 1956-5, 1957-15, and on the island of Barsakelmes: in 1942-March 1, 1943-5, 1944-5 February, 1945-22, 1946-16.
Spring 1954 in Muyunkum and in southern Balkhash was late: March of this year, much colder than in February 1953, and therefore stayed out of hibernating rodents. In early spring 1944 revival of ground squirrels on the island Barsakelmes noted a month earlier than in the previous two years.
The beginning of this occurrence in the ground squirrel hibernation over the years has remained more or less constant. Climate change does not affect the time of occurrence of the first animals. Individual stall special care to sleep under all environmental conditions. Nutritional status and weather have a decisive influence on the occurrence of animals in general. Nourished adults sleep in the comfort of the hole, until the spring of next year. Some young dream is temporarily interrupted or being exhausted, they did not fall asleep and thaw out from a hole in search of food. These animals we have met even in December and January.
The appearance on the surface of the ground squirrel in autumn is often observed after the dry summer, as early as vegetation burns and animals can not be required to accumulate a continuous hibernation fat. Conversely, when the summer is relatively humid, and the vegetation in the desert is quite developed, ground squirrels fatten fat and go to sleep even earlier than usual (used magilov, 1955, 1956). This young fit almost simultaneously with adults. After this summer, re-entering in the fall is almost not observed.
Thus, in a favorable forage wet years is the earliest occurrence of ground squirrels and friendly and this aestivation are covered not only adults, but also young birds. So there is no reason to believe that the phenomenon of aestivation yellow squirrel — is an adaptive feature, which arose in connection with the alleged burning out vegetation and the main host plants. A significant portion of ground squirrels (adult and semi) nazhirovyvayutsya enough and go to sleep to burn vegetation. Only juveniles who failed to accumulate fat, especially in adverse forage dry summer, delayed until the fall, often met at the water where stored food plants. They come out of hibernation after a long delay in the spring of next year and through them to create an extended period of awakening.
Chorus occurrence affects the timing of waking gophers of different age groups in the spring of next year. For example, in 1946, noted the almost simultaneous awakening of animals of all ages in many parts of the surveyed area. Period of awakening gopher is often quite extended, mainly because of the unfavorable weather conditions. The final output of the normal animals often prevent spring precipitation, freezing, alternating with thaws and storms. The massive appearance of rodents on the surface coincides with the onset of warm weather is stable and there is a more or less steady weather. The extension of the normal time-to gophers also due later release a large number of yearling animals due to intensive breeding population in the last year.