Interatheriidae is an extinct family of notoungulate mammals from South America. Interatheriids are known from the Paleocene or Eocene through the Miocene (McKenna and Bell, 1997). These animals were principally small-sized, occupying a habitat like hares, marmots and vizcachas.The majority were very small, like rodents. This was a group that lasted a long time, from the Paleocene to the last of the Miocene.