Dinosaur Walk Museum modern day birds. Troodon: The Troodon, a very small bird-like dinosaur, grew to be up to in length, tall and only weighed up to 130 pounds. Living during the late Cretaceous Period, 75–66 million years ago. Originally thought to be carnivorous, modern evidence shows that it is possible that they were omnivorous or possibly an herbivore. Plesiosaurs: The Plesiosaurs were carnivorous aquatic reptiles. First appearing at the beginning of the Jurassic Period they thrived throughout the Cretaceous Period. They lived during the same time as the dinosaurs but were not dinosaurs, they are considered reptiles. Oviraptor: The Oviraptor, or "Egg
Archaeopteryx or trunk-climbing lifestyle. This has been interpreted as evidence of theropod ancestry. In 1988, Gregory S. Paul claimed to have found evidence of a hyperextensible second toe, but this was not verified and accepted by other scientists until the Thermopolis specimen was described. "Until now, the feature was thought to belong only to the species' close relatives, the deinonychosaurs." The Thermopolis Specimen was assigned to "Archaeopteryx siemensii" in 2007. The specimen is considered to represent the most complete and best-preserved "Archaeopteryx" remains yet. The discovery of an eleventh specimen was announced in 2011, and it was described in 2014. It