Triceratops and Eotriceratops were some of the biggest ceratopsians, or horned dinosaurs. They could reach lengths close to 30 feet and weighed up to 20,000 pounds– more than two hippos. But while the ceratopsian family included big dinosaurs, some of their earlier relatives were tiny. Aquilops americanus was less than two feet long and weighed about three pounds. It probably walked on two legs like another early ceratopsian family, the Psittacosaurids. Some fossils of Psittacosaurids have been found with preserved bristles on their tails, a little like a porcupine.

While the word “ceratopsian” means “horned face,” not all of these dinosaurs had big horns like Triceratops. Many of the smaller earlier members of the family lacked horns, but just about all of them thick beaks that helped them snip plants to eat.

Illustration by Nobu Tamaru