A gerbil is a small mammal of the subfamily Gerbillinae in the order Rodentia. Once known as desert rats, the gerbil subfamily includes about 110 species of African, Indian, and Asian rodents, including sand rats and jirds, all of which are adapted to arid habitats. Most are primarily active during the day, making them diurnal (but some species, including the common household pet, exhibit crepuscular behavior), and almost all are omnivorous. Gerbils are related to mice and rats; they all belong to the family Muridae.

One Mongolian species, the clawed jird (Meriones unguiculatus), is a gentle and hardy animal that has become a popular small house pet. It was first brought from China to Paris in the 19th century. It was brought to the United States much later, in 1954, by Dr. Victor Schwentker for use in research. Notably, it is illegal to keep gerbils as pets in California and New Zealand.

The gerbil got its name as a diminutive form of "jerboa", an unrelated group of rodents occupying a similar ecological niche. Gerbils are typically between 6 and 12 inches (150 and 300 mm) long, including the tail, which makes up about 1/2 of their total length. One species, the great gerbil (Rhombomys opimus) originally native to Turkmenistan, can grow to more than 16 inches (410 mm). The average adult gerbil weighs about 2.5 ounces (71 g).

See also:

• mammal
• rodent
• murid
• gerbil