Family Muridae:Rats, mice and related rodents.
Subfamily Gerbillinae:The gerbils and jirds. Approximately 110 gerbil and jird species range throughout the grasslands, steppes and deserts Africa, India and central Asia (from Turkey and southwestern Russia to northern China). Some colonize cultivated land and are considered to be serious agricultural pests.
Genus Meriones:The Mongolian gerbil and the 14-20 species placed in the same genus are referred to as jirds in most books. Many live in very hot climates and are largely nocturnal. The Mongolian gerbil ranges further north than most, and is active by day.
The largest of the group, the great gerbil of Turkmenistan and nearby areas, reaches 16 inches in length. Mongolian gerbils are typically 8-9 inches long (including the tail).
Northeastern, central and southern Mongolia and nearby areas of southern Russia.
Flat, arid steppes populated by grasses, herbs and low shrubs. Temperatures range from well below freezing to 120°F; periods of extreme weather are spent below-ground in communal burrows.
Mainly seeds, although buds and insects may be taken on occasion. Mongolian gerbils rarely encounter free-standing water. Their digestive systems effectively extract water from food; only a few drops of highly concentrated urine are produced at any one time.
Reproduction and Social Behavior
Mongolian gerbils are social rodents with a fascinating reproductive strategy.
Social groups consist of 1-3 adult males, 2-7 adult females and several sub-adults and juveniles. They share a common burrow and cooperate in storing food for the winter and in driving off unrelated gerbils and other rodents (in captivity, it is extremely difficult to introduce a new gerbil into an established group).
Their mode of reproduction has been reported to fall into one of two possible patterns, although the factors determining which predominates are not well known. In some colonies, mature females leave the group to mate with unrelated males living nearby, after which the females return to their original colony. There they give birth and raise the young, assisted by "uncles" and other relatives.
In the alternative strategy, only the dominant pair of gerbils in the colony reproduces, with others bearing young only when one of the dominant pair dies.
Captives breed year-round, but in the wild the mating season lasts from February to October, during which time up to 3 litters are produced by each breeding female. The young are weaned at 20-30 days of age, and reach sexual maturity in 65-85 days. Pet gerbils may live as long as 5 years, but wild individuals rarely survive for longer than 4 months.