The earliest Prehistoric animals to live were jawless, spineless creatures that roamed the oceans about 540 million years ago. It wasn’t until the Devonian period, 400 million years ago, when the prehistoric creatures grew legs and left the ocean, these are the prehistoric ancestors to all vertebrate creatures on earth today. Once on land, the prehistoric creatures underwent a bunch of different adaptations for running, crawling, flying, and jumping; it was then when the rise of the dinosaurs took place, in the Triassic period about 230 million years ago. Even though the dinosaurs ruled, many small, rodent-like mammals were alive and these small mammals, along with some birds, amphibians, and reptiles survived the mass extinction that wiped out the dinosaurs. Although 90% of the species that have lived on Earth throughout its existence are extinct, most of the creatures that survived this first mass extinction still exist today.
Tyrannosaurus Rex (T-Rex) was one of the largest predatory dinosaurs that ever existed. Living during the Cretaceous period (68-66 Mya) in the forested river valleys of today’s western North America, Tyrannosaurus is a carnivore popularly known for its large 5’ | 1.5 m skull, ferocious serrated teeth, small useless arms, strong tail, and powerful bipedal legs. Tyrannosaurus Rex was 40’ | 12.3 m in length, with a head height of 17’ | 5.2 m and hip height of 12’-13’ | 3.7-4 m.
Height (Hips): 12’-13’ | 3.7-4 m
Period: Cretaceous (68-66 million years ago)
Scientific Name: Tyrannosaurus
Tyrannosaurus | T-Rex side elevation, front, back, plan
Stegosaurus was a Late Jurassic (155-150 Mya) herbivorous quadrupedal dinosaur known for its array of upright plates on its back and strong spiked tail. Heavily built with short limbs, a small head, and large body, Stegosaurus was a defensive dinosaur that likely foraged for twigs and low hanging fruits. Stegosaurus has a body length of 30’ | 9.1 m and a height of 14’ | 4.3 m.
Triceratops were three-horned herbivorous dinosaurs that roamed western North America in the late Cretaceous period (68-66 Mya). Combined with a shield-like head plate, the horns of the Triceratops were likely used to protect them from predators and may have also been used for mating rituals. The Triceratops had a length between 26’-29.5’ | 7.9-9 m and stood 9.5’-10’ | 2.9-3 m tall.
Period: Late Cretaceous (68-66 million years ago)
Scientific Name: Triceratops
Triceratops side elevation, front, back, plan