Of the two existing generic representatives of the Camelidae (as the family in which they are both included is named), the Old World camels (Camelus) are characterized by their great bodily size, and the presence of one or two fleshy humps, which diminish or increase in size according to the physical condition of the animals themselves.
Although the name llama properly applies only to one of the domesticated breeds, zoologically it is taken to include all the South American representatives of the Camelidae, which form the genus Lama.
All the foregoing genera are included in the sub-family Camelidae.
It is not easy to point out the characters in which the family approximates to the Camelidae, and only its general characteristics can be indicated.
The disagreeable habit of spitting is common to all the group. In a wide sense the term "llama" is used to designate all the South American Camelidae.