Hibernate in the fridge: jerboas fell asleep in the Moscow Zoo

December 18, 2019
Parks and pedestrian areas

Jerboa have fallen asleep in the Moscow Zoo.  There are five of them — four great jerboas and one long-eared one. Due to the unusually warm autumn, their hibernation has been postponed. The next three to four months jerboas will spend in a special refrigerator with a temperature between +2-4°C. Last year, they were sent to hibernate late in September to sleep until mid-March.

Before the onset of cold weather, visitors to the Zoo could see jerboas in the Nocturnal World. Now the animals have been removed from their habitual enclosures to come back later, when hibernation ends, approximately in March.

In the wild, jerboas also hibernate at different times depending on the air temperature and available food supplies. If the animals have enough food, they go on feeding, even when it's cold. If there is a shortage of food, they prefer to fall asleep, so as not to waste fat reserves accumulated over the summer. As a rule, jerboas hibernate when the temperature is about +4°C.

'Zoologists make sure that the life cycles of our jerboas are the same as those of their relatives living in the wild. There is always a change of season in the room where the animals are kept (ambient temperatures change depending on the time of the year), with their diet adjusted, too. In spring and early summer, animals eat more carrots, apples and fresh grass. In the second half of summer and early autumn, when rodents need to gain weight and prepare for hibernation, much of their daily ration includes highly nutritious food, such as a grain mixture with plenty of sunflower seeds. Thanks to this diet, jerboas gain enough body weight by mid-autumn, when it's time to go into hibernation for about four months and stay healthy,' said Svetlana Akulova, Director General of the Moscow Zoo.

Since each jerboa has its own weight gain dynamics, Zoo specialists have monitored the change in body weight of each animal. Jerboa are sent to cold storage only when they reach optimal weight. Just before hibernation, the weight of a great jerboa was about 400 g. Over the winter, they can lose up to a quarter of their weight. The long-eared jerboa is smaller: before falling asleep, it weighed only 75 g, and after waking up the weight of the animal will not exceed 45 g.

In the jerboa enclosure, the temperature has been gradually reduced for them to feel the approach of cold weather. When the animals were ready to go into hibernation, zoologists placed each of them in separate foam-upholstered wooden boxes to move them to the cold storage.

Throughout the winter, the animals will be weighed once a week. Specialists carefully take rodents out of the refrigerator, inspect them, weigh and check other vitals. If an animal is OK, losing weight gradually, it goes back to the refrigerator. If a jerboa loses weight too quickly, specialists wake it up and feed it.

The rodents will come out of hibernation when their body weight reaches summer values. Great jerboas should weigh 260–300 g. Long-eared jerboas have to reach 45g. The awakening process takes several hours. When the animals finally wake up, they quickly return to their normal life. They are very active and boast an excellent appetite.

With the onset of cold weather, the Bat Wintering Centre opened in Moscow Zoo. You can bring bats there to help them survive the winter or report an animal's location to the zookeepers.  In the centre, the animals get enough food to gain weight they need for proper hibernation, and then placed into a refrigerator. In May, they are released into the wild.

In late November, three bears fell asleep in the Zoo. 27-year-old Kamchatka brown bear Rosa and her neighbours, Himalayan bears Aladdin (25 years old) and Budur (24 years old), hibernated in their dens in closed enclosures. They will sleep there until spring.

Raccoons and raccoon dogs will soon hibernate, too.

Since 1 November, the Zoo has been working in the winter mode. Visit Asian elephants, polar bears, giant pandas and other animals 09:00 am till 05:00 pm. Ticket offices are open 09:00 am till 04:00 pm.

The winter mode will last until 28 February. During the cold season, guests can also visit heated pavilions and indoor enclosures, such as the Monkey House, home to Bornean and Sumatran orangutans, lowland gorillas, lion-tailed macaques and other primates. In winter, you are welcome to the Bird House with penguins, cassowaries, parrots and other birds. You will find animals who like cold weather such as polar bears, Northern and Baltic seals, common and polar wolves, foxes, Arctic foxes, snow leopards, cougar, Eastern European lynx, musk oxen, Amur leopard, Dagestan tours, markhoors and bharals in open enclosures.

Source: mos.ru

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