Ceratosaurus was a powerful predator that walked on two strong legs, had a strong, s-shaped neck, and had a short horn on its snout. It had a massive tail, a bulky body, and heavy bones. Its arms were short and it had four-fingered hands (a primitive configuration) with sharp claws. It also had large eyes (and therefore probably had very good eyesight).Ceratosaurus was 15 to 20 feet long (4.5 to 6 m) long, weighing roughly 0.5 to 1 ton (500 kg to 1 tone). It had a skull a snout horn and two short brow ridges, and bony knobs and ridges above its eyes and on the top of the head. This common hunter had large, powerful jaws with long, sharp, teeth. Ceratosaurus was a large but common meat-eater from the late Jurassic period, about 156 million to 145 million years ago. Ceratosaurus was a carnivore, a meat eater. It was a large, fierce predator that could kill even large sauropods. Ceratosaurus may also have been a scavenger.

Coelophysis:

Coelophysis (pronounced SEE-low-FIE-sis) was a small, lightly-built dinosaur that walked on two long legs. This predator was about 9 feet long (2.8 m). It had light, hollow bones (hence its name), a long, pointed head with dozens of small, serrated teeth, three clawed fingers on its hands, and a long neck.Two types of Coelophysis fossils have been found, 'robust' and 'gracile.' These two forms probably represent males and females.Coelophysis lived during the late Triassic period, roughly 210 million years ago; it was one of the earliest-known dinosaurs. Coelophysis lived in what was then a seasonally dry, desert-like environment, a savanna-type climate perhaps like modern-day Kenya without the grasses (since flowering plants hadn't evolved yet).Coelophysis was a carnivore, a meat eater. It may also have been a scavenger. Coelophysis' fossilized stomach remains have been found containing small reptiles, fish, and other Coelophysis bones of different sizes, indicating that it was a cannibal.

Compsognathus:

Compsognathus was a bird-like dinosaur that walked on two long, thin legs; it had three-toed feet. A long tail acted as a counterbalance and for stability during fast turns. It had short arms with two clawed fingers on each hand. Compsognathus had a small, pointed head with small, sharp teeth, hollow bones, and a long, flexible neck.Compsognathus was from 28 inches-4.6 feet long (0.7-1.4 m), about 6.5 pounds (3 kg) and was about the size of a chicken. Its femur (thigh bone) was only 4. 3 inches (11 cm) long. Compsognathus lived in the late Jurassic period, about 155 to 145 million years ago. Among the contemporaries of Compsognathus were Coelurus and Ornitholestes.Compsognathus was a carnivore (a meat eater) that caught and ate small animals, including insects and lizards. John Ostrom found fossilized remains from a Compsognathus' stomach that contained the skeleton of the fast-running lizard Bavarisaurus.

Deinonychus:

Deinonychus was a lightly built, fast-moving, agile, bipedal (walked on two legs), bird-like dinosaur. It was built to kill. This meat-eater had a curved, flexible neck and a big head with sharp, serrated teeth in very powerful jaws. Each of its three fingers on each hand had large, sharp, curved claws. It had four-toed feet; the second toe had a 5-inch (13-cm) sickle-like claw, and the other toes had smaller claws. Its long tail had bony rods running along the spine, giving it rigidity; the tail was used for balance and fast turning ability. Deinonychus had a relatively large brain and large, keen eyes.Deinonychus was about 10 feet long (3 m), 5 feet tall (1.5 m), and weighed up to 175 pounds (80 kg). This dinosaur was roughly 4 ft (1.2 m) tall at the shoulder. Its femur (thigh bone) was 31 cm long.Deinonychus lived during the Cretaceous period, about 110 to 100 million years ago. Among the contemporaries of Deinonychus were Spinosaurus, Archaeornithomimus (another swift, bird-like theropod), Sauroplites (an ankylosaurid, a plated herbivore), Sauropelta (a nodosaur, another armored herbivore), Probactrosaurus (an iguanodontid), Titanosaurs (a sauropod), and Tenontosaurus (a hypsilophodontid). Deinonychus was a carnivore, a meat eater. It probably ate just about anything it could slash and tear apart. When hunting in packs, Deinonychus could probably kill any prey it desired.

Dilophosaurus:

Dilophosaurus was a double-crested lizard and it is speedy, slender, bipedal (walked on two legs), meat-eater that lived during the early Jurassic period. It was a theropod (a meat-eating dinosaur) about 20 feet (6 m) long, about 5 feet (1.5 m) tall at the hip, and weighing about 650 to 1,000 pounds (300 kg to 450 kg).

It had two thin, bony, almost semi-circular crests on its head; these may have been for mating displays. It had short arms with three-fingered hands and strong legs with four-toed feet (one toe was a dewclaw). Both fingers and toes had claws. It had hollow bones and an S-shaped, curved neck. Dilophosaurus lived about 201 to 189 million years ago, during the early Jurassic period. Among its contemporaries in North America during this time, all smaller than Dilophosaurus, were:

• the meat-eaters Coelophysis (about 10 feet long), Syntarsus, and Segisaurus
• the omnivores Massopondylus and Anchisaurus
• The plant-eaters Scutellosaurus and Ammosaurus.

Dilophosaurus was a carnivore, a meat eater. It had loosely attached jaws which would have made killing animals with its teeth difficult. It must have killed with its clawed arms and legs, and/or scavenged carcasses.

Eoraptor:

Eoraptor (pronounced EE-oh-RAP-tor) is one of the earliest known dinosaurs. It was a very small carnivore (meat-eater) that lived during the late Triassic period, about 228 million years ago. Recently, even older dinosaurs have been found in Madagascar. Eoraptor was a small, lightly-built dinosaur that walked on two long legs. It was about 3 feet long (1 m); it had light, hollow bones, a long head with dozens of small, sharp teeth, and five fingers on its grasping hands (two of the fingers on each hand were very small). Eoraptor was a saurischian ("lizard-hipped") dinosaur, a very primitive theropod, and a member of the infraorder Herrerasauria (which includes Herrerasaurus, Staurikosaurus, Saltopus, and other very early dinosaurs). The type species is Eoraptor lunensis (named by Paul Sereno, Forster, Rogers and Monetta in 1993).Eoraptor lived during the late Triassic period, roughly 228 million years ago. It is one of the oldest dinosaurs yet found.Eoraptor was a carnivore, a meat eater. It may also have been a scavenger.

Gallimimus:

Gallimimus was a fast-running dinosaur with a very long, thin, flattened, toothless, horny beak, a small head, and a relatively large brain. The bottom front part of its beak was shaped like a shovel. It had large eyes positioned on opposite sites of its head, ruling out binocular vision (depth perception). It had a long neck, long tail, and long legs. Gallimimus was about 13-20 ft (4-6 m) long, was 6.3 ft (1.9 m) tall at the hips, and may have weighed about 970 pounds (440 kg).This oviraptorosaur had short arms with three clawed fingers on each hand, and long legs with three clawed toes on each. A long tail acted as a counterbalance and as a stabilizer during fast turns. Its bones were hollow.Gallimimus lived in the late Cretaceous period, about 75-70 million years ago.Gallimimus may have been an omnivore, eating small animals (like insects and lizards), eggs, and some plant material, by sieving them from mud with comb-like plates in its mouth.

Giganotosaurus:

The longest meat-eating dinosaur yet discovered is Giganotosaurus, a 44-46 ft (13.5-14.3 m) long behemoth, who weighed about 8 tons and stood 12 feet tall (at the hips). It walked on two legs, had a brain the size of a banana, and had enormous jaws with 8-inch long serrated teeth in a 6-foot (1.8 m) long skull. Giganotosaurus was a theropod from the mid-Cretaceous, living about 100-95 million years ago, toward the end of the Mesozoic Era, the "Age of Reptiles".Giga-noto-saurus means "giant southern reptile". Its fossil was unearthed in Argentina in 1994. 70 percent of the skeleton has been found. Near the Giganotosaurus, fossils were found of 75-foot-long plant eaters, presumably victims of this Giganotosaurus. Giganotosaurus lived about 95 million years ago, during the late Cretaceous period. This was about 30 million years before Tyrannosaurus rex, which was among the last of the dinosaur species alive before the Cretaceous-Tertiary extinction 65 million years ago.

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