The second family of rhinoceroses is termed the Amynodontidae. The Amynodonts are thought to have been descended from the more primitive Hyracodonts. This family of rhinoceroses is found in the late Eocene and Oligocene in Europe and America. Amynodonts are also found in Asia, where they persisted until the Miocene.

Amynodontidae displayed a larger body size than that of the Hyracodonts. The body is around the same general size of a Hippopotamus, and they displayed short massive limbs. The conditions that some of the remains are found in suggest that there might have been some river living forms of Amynodontidae.

Metamynodon, a species of Amynodontidae, was 4m (13 ft.) in length .
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