Gerbils belong to to the Muridae family of Rodents, which includes mice, but are in their own subfamily, the Gerbillinae. They are omnivorous, and are active mainly in daylight and/or just before nightfall.
The Mongolian gerbil is stocky and well adapted to life in the extreme climate of the Central Asian steppe and semi-desert that it’s wild cousins call their home. The tail is furred to provide additional protection against the cold and they even have fur between their toes.
All gerbils are adapted to live in very dry environments, and have have evolved to conserve moisture. This means they drink only small amounts of water, and never smell.
Gerbils have very good eyesight and a keen sense of smell. Their hearing is around seven times better than humans helping them hear danger approaching.
Excluding the relative giants of the family, most gerbils are between 6 and 12 inches long. Their tails make up about half this total length. The average adult gerbil weighs about 2.5 ounces.
Like all rodents, gerbils have front teeth (incisors) that constantly grow throughout their lives, but are constantly worn down to optimum length by the hard food they nibble on.