Caviinae is a subfamily uniting all living members of the family Caviidae with the exception of the maras, capybaras, and Kerodon. The subfamily traditionally contained the guinea pig-like forms along with the cursorially adapted (running) Kerodon.  Molecular results suggest the Caviinae as so defined would be paraphyletic and Kerodon is more closely related to maras and capybaras than to other caviines. This led Woods and Kilpatrick (2005) to unite Kerodon and capybaras into the subfamily Hydrochoerinae within the Caviidae. These studies also suggest Microcavia and Cavia are more closely related to one another than either is to Galea.