Sleepyheads: which of small mammals fell asleep at Moscow zoo


With the onset of cold weather, such large animals as Brown and Himalayan bears plunged into winter sleep. But there are some much smaller animals, including chipmunks, forest dormice and loirs, Madagascar hedgehogs, white-breasted hedgehogs, that have hibernated as well. All of them prefer to spend a winter season in a state of suspended animation, when there is lack of feed in nature.

Jerboas are the first animals plunged into hibernation this year. In the summer they have actively accumulated fat reserves, and as soon as their weight reached 450 g, zoologists put them in special boxes covered with foam rubber, which were put in a special refrigerating chamber. There, at a stable temperature level, the jerboas will sleep until the onset of warmth. By that time, the animals will lose about a third of their weight. During hibernation, all metabolic processes in the body of jerboa are slowed down; the body temperature also falls to 8 degrees, the frequency of its heart rate and breathing decreases. During this time, the jerboa rolls up into a ball and, without waking up, crawls into a place with optimal temperature.

The specialists begin to prepare the jerboas for hibernation long before the onset of winter.  Since the end of August, the temperature in the room where the jerboas are kept, is gradually reduced, and the animals eat more and more fat seeds and less juicy fiber-rich feed. At the same time, zoologists monitor the well-being of animals and, most importantly, the dynamics of their weight gain. During the preparation process, the weight of jerboa is constantly growing, and when the weight gain stops, this means that the animal is ready for hibernation. During the winter the jerboas have been weighed once a week and, as soon as the weight reaches the summer parameters, the jerboas are moved to a warm place.

Unlike the jerboas, forest dormice and loirs hibernate in the outdoor enclosure. Long before the onset of cold weather, zoologists provide the animals with wolf and camel wool, from which they build nests - dormice hide and sleep in it until spring. They regulate the moment of falling asleep and out coming from hibernation. The case with white-breasted hedgehogs is similar. They fatten up all summer, and when they reach the necessary weight (about 1300 g), they bury themselves in hay, dry leaves and hibernate until spring. This year one hedgehog has felt asleep in the outdoor enclosure at the “Fauna of Russia” exhibition, two others - in the “Night World” pavilion, and three more specimens have hibernated in the enclosure of owls at the new territory of the zoo. According to the experts, the white-breasted hedgehogs will wake up in March (if the weather is good) or early April (if the cold stays in the capital).

The situation with Madagascar hedgehogs is a little bit different. These amazing animals have incomplete thermoregulation and their body temperature is highly dependent on the environment. They need a temperature regime above 25 degrees for a comfortable life and 28 degrees for reproduction. They can sleep at a temperature of about 20 degrees. Moreover, they spend 5-6 months in a state of hibernation.

We say goodbye to the forest dormice, jerboas, hedgehogs and other "sleepy" inhabitants of our zoo until spring. We wish them sweet dreams!