Protoceratops was a small protoceratopsian dinosaur that lived in Mongolia and other parts of Central Asia during the Late Cretaceous. Many predators hunted down protoceratops like Velociraptor or Tarbosaurus. It is a member of the family Protoceratopsidae which resemble the larger Ceratopsidae (the family that includes Triceratops and Styracosaurus) except that they are smaller and more primitive with less horns and smaller frills. The protoceratopsians share a common ancestor to the ceratopsians which explains why they both live in the Late Cretaceous.
Protoceratops had predators like Velociraptor to keep its numbers down. A famous fossil shows a lone Velociraptor take down a lone Protoceratops. The Velociraptor slashed the herbivore's throat while the Protoceratops bit the raptor's arm and broke it. Both are claimed to have died by a sandstorm right when they were about kill each other.
The Land Before Time
A ceratopsian, possibly Protoceratops, makes a brief cameo near the end of 'The Hidden Canyon', an episode of the television series.