This is Dimetrodon, a vicious carnivore. The biggest reptile on Earth.
— Allen, about Dimetrodon

Dimetrodon (name meaning "Two Measured of Teeth") is a genus of pelycosaur synapsid, a species of carnivorous, non-therapsid mammal-like reptile, that originated during the Early Permian period. It was the top predator of its time.

Dimetrodon is of the strange and iconic looking 'sailbacks', that are often incorrectly referred to as Dinosaurs. Fossils of them are known from North America and Europe. They were the largest predatory Pelycosaurs ever, at 3.5 meters long and weighing over 500 pounds. They were formidable carnivores in their day, preying on even their 'own kind', as in other Pelycosaurs such as Edaphosaurus

It is most likely they were even cannibals, not being above preying on newly hatched infants of their own species when given the chance to. Dimetrodon is also known for being one of the most famous prehistoric creatures in the world. 


Era and DiscoveryEdit

Dimetrodon lived during the Early Permian period 280–260 million years ago. It was the apex predator of its time. Dimetrodon was first described in 1878. Fossils of Dimetrodon have been found in North America and Europe, as well as significant discovery of Dimetrodon footprints in southern New Mexico by Jerry MacDonald.

Physical AttributesEdit

Dimetrodon was a large, quadrupedal apex predator, among the largest of its day, notable for its very large spinal sail. It grew to up to 11 feet (3.4 m) in length and weighed 250 kilograms (550 pounds), the size of an alligator or big cat. Additionally, when Edaphosaurus flushed blood into their sails to distract predators from their heads, Dimetrodon was somehow able to see through their disguise. It was green with a white underbelly. Its sail was green and orange and was decorated with striped and circular patterns.


Dimetrodon's teeth

As well as their utter power and size, Dimetrodon possessed a killer edge; as a protomammal, or mammal-like reptile, they evolved specialized teeth. Their incisors sheared of chunks of flesh, while their serrated canines cut and sliced the flesh. Although having inherited the same form of meat-eating teeth, humans today, however, have a smaller version.

Behavior & TraitsEdit

Dimetrodon was a solitary hunter, only getting together in groups during mating season or scavenging off a kill. Though Dimetrodon generally attack adult Edaphosaurus, pregnant females who were just about to lay their eggs preferred to steer clear of getting injured, and therefore attacked smaller and younger Edaphosaurus. Whenever they hunted animals, such as Edaphosaurus, Dimetrodon first started off with mock charges, tactics to disperse the group and expose the vulnerable youngsters.

When female Dimetrodon were pregnant, their kills were crucial. Before they could lay their eggs, they needed to eat enough food that would last them for seven long months of their eggs incubation. And to increase their babies chances of survival, the females evolved a basic form of parental care: guarding their eggs. For example, when a female had already laid her eggs, she would defend them fiercely from anything, weather a thieving scavenger or even another female Dimetrodon. And once the eggs hatched, the females duty of guarding their eggs would be done and their goal achieved, but however, her maternal bond with them would then be severed. Unlike their mammalian descendants, female Dimetrodon would not and never nurtured their young. After they hatched, the females first and only instinct was to save themselves by searching for food.

Male Dimetrodon were highly aggressive and when it came to them scavenging for food, even females knew better than to defend their kill. While lions today consume 70% of a carcass, Dimetrodon ate 90%. By the time a group of Dimetrodon was finished eating, there would be nothing left but the bones of their food. However, they only ate intestines after shaking out the waste inside. Dung is one thing a Dimtetrodon couldn't stomach.

Additionally, adult Dimetrodon were cannibals, even going as far as to eat baby or even hatchling Dimetrodon, even if the adult Dimetrodon was the hatchlings mother. They would weed out weaker babies straight away, which helped the strong ones and her species as a whole survive. Whenever hatchling Dimetrodon hatched from their eggs, they would have to be ready to go it alone without their mothers protection. They came out of the nest and made quick dashes for the safety of the trees. Whilst some were caught by adults, not all babies were helpless. Some already knew instinctively how to defend themselves. They rolled in dung, something adults can't stand, repelling their pressures long enough to get as head start. And hatchlings could also climb up trees.

Journal EntryEdit

The apex predators of the Permian age, Dimetrodon, "Two Measures of Teeth", were at the top of the food chain in their bay. Just as large as Edaphosaurus, these sail-back, mammal-like reptilian carnivores were the Edaphosaurs' greatest enemy. In addition to their sheer size and overall power, they also evolved specialized, meat-eating teeth; incisors shear off flesh whereas their serrated canines cut and slice. Buy the time a Dimetrodon were finished with their food, there would be but the bones of their food left.

While Male Dimetrodon were highly aggressive, the females were more solitary and they also evolved a form of care for their young, guarding them even from other desperate pregnant females. It appears that when the pregnant females make a kill, they need enough food to last them for seven long months before their eggs are born. The moment the hatchling Dimetrodon are born, the females appear to not care fore their young anymore and abandon them. It seems that the female Dimetrodon don't nurture their young and would even go as far as to eat them, hinting a form of cannibalism between these creatures.

— Allen, in his Journal, about Dimetrodon