Two Neuquensaurus stand on their hind legs to reach the top of a tree. Computational analyses indicate that the species could easily have remained in this position 66 million years ago. Credit: Guilherme Gehr Around 66 million years ago, two types of long-necked, four-legged dinosaurs stood out from other sauropods. They had the ability to rise up on their hind legs and stay upright for extended periods. This posture likely helped them reach leaves high in trees and may have made them look