Late Cretaceous - 65 Mya
North America: Colorado, Montana, South Dakota, Wyoming, Alberta, Saskatchewan
Length: 9 meters (25 – 30 feet)
Height: 3 meters (10 feet)
Weight: up to 10,000 kg (22,000 lb)
Juveniles and sub-adult dinosaurs were not just smaller versions of adults. Before they reached full adulthood the horns and frills of Triceratops underwent several changes. As a juvenile, the horns were much smaller buds, lengthening and curving backwards toward the frill as the dinosaur grew to the sub-adult stage. In the final growth stage to adulthood the horns shifted forward.