The most common type of gerbil kept as a pet is the Mongolian gerbil, which has been kept domestically for some 30-years. Domestic gerbils come in a variety of colors including black, slate blue, gray, white, brown, gold, orange, and a mixture of many colors. Some gerbils have patterns or spotting, which produce a white patch on the forehead and a white collar-like marking around the neck and tail. Mongolian gerbils are 4-6 inches long, excluding their flexible, hair covered tail. Gerbils have large eyes and ears and long hind legs.
Gerbils are social animals in the wild and tend to fair better when coupled with another.
Two female gerbils can safely be kept in the same living environment. Two males kept in the same space tend to fight for dominance. Gerbils are affectionate rodents, who will play and interact well with their owners. They're also extremely intelligent and will go to great extremes to keep themselves occupied. This is another good reason why two are better than one.