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A highly adaptable little carnivorous dinosaur that was both an active hunter and a scavenger. Probably solitary most of the time, but during the dry season would occasionally concentrate in large groups around food and water resources.

– Description
Walking with Dinosaurs: A Natural History

Coelophysis is a 3-meter long theropod dinosaur from the Norian stage of the late Triassic period.


It lived in North America during the Late Triassic period (around 230 MYA). It was also among the first of the dinosaurs ever to appear on Earth.

Coelophysis and other early dinosaurs were light boned, fast, and they are beautifully adapted for killing. But what made them unique are special hips and ankles that allowed them to stand perfectly balanced on two hind legs. They also could make noise without using much precious water. With lightning fast reactions, they were built to survive. This was unlike other sauropsids at the time, and a unique trait of the averesmentalians.

It was their speed and agility that gave them the edge in the Triassic. When their numbers are on the increase, this leads to confrontations. They were opportunistic feeders and would eat anything that moves. 

Coelophysis was built to be a slender, agile reptile with a long neck and tail, perfect for searching scorpions, lizards and other small animals that may be hiding under rocks, in holes, or on trees. However, by the time the Jurassic period arrived, new theropods appeared on the scene, like Dilophosaurus. They were bigger and stronger than Coelophysis and better adapted to fill-in the carnivores' eco-niche - and so they drove Coelophysis to extinction.

In Walking with Dinosaurs

"New Blood"

Two Coelophysis were seen running through a desert during a drought. A female was later seen at a river fishing for lungfish. She managed to kill one but before she could eat it, a Placerias scared her off. The female Coelophysis was then seen standing by a herd of Placerias waiting for old and sick individuals to lose the herd. She confronted an old Placerias but her presence was not tolerated.

Two Coelophysis were seen investigating a Thrinaxodon burrow. However, the cynodonts inside scared off the inquisitive pair. When the male cynodont left the burrow to hunt, the female Coelophysis killed one of their pups. The Coelophysis is then seen digging up the cynodont burrow. During the night, the cynodonts escaped. In the morning, the Coelophysis continued digging it up but it took them a while to realize that their work was in vain.

During a drought, the female Coelophysis was seen digging up a lungfish in a protective cocoon. However, before she could eat it, several other Coelophysis appeared and challenged her for the carcass. They screeched at each other and one of them won the lungfish. As the population of Coelophysis had become higher, they had united to form flocks. A flock was seen harassing a dying female Postosuchus. When the Postosuchus eventually died, the flock dined on the colossal corpse. The flock was seen staying at the shrunken river. With the rarity of food and water, the starving animals had resorted to cannibalism. The flock then moved on to find more food and water. During the night, a male cynodont was seen killing a young Coelophysis before returning to his burrow.

Plateosaurus scaring away a Coelophysis

During the late-arriving wet season, the female Coelophysis was seen drinking from a waterfall with others of her kind but as a large herd of Plateosaurus arrived, she retreated.

In Walking with Dinosaurs: A Natural History

"New Blood"

A male Coelophysis first appeared stalking a lungfish which was finishing off a crayfish. After careful observation, the Coelophysis struck the lungfish and threw it out the water. The dinosaur then pinned the lungfish down and dismembered it. Within five minutes, he finished his meal and then headed off to find shade.

Later, two Coelophysis discovered a burrow containing two Thrinaxodon. The larger of the two peered into the burrow but was alarmed when a male Thrinaxodon emerged. The Coelophysis barked as he tumbled down the bank away from the angry parent. Knowing the Thrinaxodon is too big a meal, the Coelophysis trotted away and stopped at 50 meters to watch. The male Thrinaxodon then returned to his agitated family. The Coelophysis then left.

During the night, as the Thrinaxodon parents left to hunt, the Coelophysis attacked and killed a pup that clambered out of its burrow after its father. The father heard his pup's squeals of pain and returned to the burrow but he was too late. The Coelophysis then accelerated away down the riverbank.

In the morning, the Thrinaxodon burrow was under siege by several Coelophysis. The male Thrinaxodon returned to flush out the attackers but his attempts were futile. As he left, the Coelophysis began to dig up the burrow. Despite several attempts to chase away the dinosaurs during the night, the Coelophysis kept on reappearing. In the morning, as the Thrinaxodon pair sought refuge, the Coelophysis were surprised by their exit. One large female attempted to pursue the pair but the male Thrinaxodon attacked her. The rest of the Coelophysis continued to dig at the burrow again.

During the height of the dry season, the forest around the river was slowly filling with Coelophysis and as a result, they became pack hunters. One finds a dying Postosuchus. He was then joined by 40 to 50 other Coelophysis who then surrounded the Postosuchus. The Postosuchus lunged at a female Coelophysis and managed to catch its foot. It then pinned the Coelophysis with its front claws and severed her neck. As the Postosuchus attempted to protect its shoulders, the rest of the Coelophysis dragged away the dead female and then devoured her. As the Postosuchus' movements became less and less frequent, the Coelophysis climbed on top of it and feasted on its corpse from the inside out.

A lone Coelophysis was later seen overlooking a whip scorpion who was laying her eggs. The Coelophysis then attacked her but she pulled back into a Placerias skull. The Coelophysis got too close and the scorpion sprayed a cloud of acid onto his face. The Coelophysis fell back, scratching at his nostrils which were burning as a result of the acid. The Coelophysis persisted in attacking again and was rewarded with another spray of acid. Irritated and in pain, the Coelophysis once again attacked the whip scorpion and ate her. Its efforts were hardly worth it.

Despite the drought, Coelophysis numbers were still high. A small flock tracked down an old riverbed and spread out to hunt. Two Coelophysis bickered over a dismembered centipede, one immature Coelophysis hid under a cycad. Several adult Coelophysis chased the youngster. The leader of the flock flung the youngster into the air by its tail. As he landed, the youngster tried to regain his footing but the jaws of his elder closed swiftly on his neck. When the young Coelophysis gone limp, the second adult immediately tried to snap and tug at the body. The killer then had to run to the scrub to avoid losing his prey to the rest of the flock. Several other Coelophysis pursued him.

As the start of the wet season began, hundreds of Coelophysis were swept away by a wall of silt and water. Very few Coelophysis managed to escape. The victims were buried under tonnes of silt in the lowland swamps along with several phytosaurs.

During a night for hunting, the male Thrinaxodon found and killed a young Coelophysis. A group of several Coelophysis was later seen fleeing across the riverbank as a fully grown female Plateosaurus blundered out of the undergrowth.

Behind the scenes

There is no evidence that Coelophysis was a cannibal.  The bones found in the famous specimen's stomach are now believed to that of a small species of crocodilian. (However, it could have been one, as they have found evidence of dinosaur cannibalism)

The model of Coelophysis was retextured and its vocalizations were reused for the Triassic coelurosaur.

Coelophysis probably didn't feed on live and healthy Placerias on their own. Coelophysis had sexual dimorphism, unlike the ones in the show, which were all the same.

No theropod had pronated wrists.

Coelophysis didn't live at the same time as Placerias. However, they were both from the Ghost Ranch Formation.

Coelophysis didn't coexist with Plateosaurus, who lived in Europe, not North America. It also did not live at the same time as Coelophysis.

Coelophysis didn't live 220,000,000 BCE. It evolved at least 203,000,000 BCE and lived to at least into the Early Jurassic approximately 196,000,000 BCE or possibly even later.

List of appearances