This Sub-family is characterised by the presence, in all its members, of
cheek-pouches, and a simple stomach. The tail is variable in length, being
long or externally invisible. The callosities on the ischiatic bones are
large; in many species they become very turgescent at certain seasons, the
enlargement extending sometimes to the tail. The hues of the skin on and
round the face also become more vivid periodically. {253}Many of the
species of this Sub-family are arboreal; some, however, are found only in
barren rocky regions; others in low jungle in the neighbourhood of
villages, water-tanks, and cultivated patches. Fruits and insects form
their principal diet.