Extant camelids (llamas and camels) are unique among wild mammals in their regular employment of a pacing gait. They also have a unique foot morphology, assumed to be an adaptation for this mode of locomotion: their feet are secondarily digitigrade, with the loss of hooves and the addition of a broad foot pad. We examined 22 measurements of the metapodials and phalanges of camelids and ruminants with bivariate and multivariate analyses, including 18 genera of extinct camelids from the Tertiary of North America. Extant camelids and ruminants were clearly distinguishable from each other. Most extinct camelids showed some morphological features typical of extant forms, five out of eighteen clustered with the extant camelids. Pacing may have evolved independently within the subfamilies Camelinae and Protolabinae. Additionally, evolutionary change towards a condition resembling that of extant camelids also occurred within the subfamilies Stenomylinae and Miolabinae. These parallel changes in camelid locomotor anatomy occurred in the late Oligocene or early Miocene, preceding the formation of widespread open grassland habitats in the late Miocene.