A
gerbil is a small mammal of the order
Rodentia. Once known simply 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
diurnal (though some, including the common household pet, do exhibit
crepuscular behavior), and almost all are
omnivorous.