The Smartest Dinosaur (and 9 More Clever Prehistoric Reptiles)

Often considered the Einstein of dinosaurs, Troodon had a relatively large brain for its body size. Fossil evidence suggests it had excellent eyesight, stereo vision, and a keen sense of hearing.

Some paleontologists argue that Troodon might have hunted in small groups, suggesting advanced cognitive abilities.

This birdlike dinosaur lived during the Late Cretaceous period, around 75 million years ago. Its name means "wounding tooth," but it's the Troodon’s brain that grabs attention in studies of dinosaur intelligence.

While Troodon is part of this group, other troodontids also rank high in dinosaur intelligence. These small, birdlike predators had some of the largest brains relative to body weight in the dinosaur world.

Their anatomy — stiff tails, grasping hands, and stereoscopic vision — suggests they had keen sensory abilities and agility, and they may have engaged in some social behavior. Troodontids are the closest thing the fossil record gives us to intelligent, non-avian dinosaurs.

Deinonychus had a brain-to-body ratio similar to the modern ostrich. That’s impressive for a predator from the Early Cretaceous period. It was agile, walked on two legs, and likely used pack hunting strategies.

This apex predator had a strong sense of balance and coordination. Its agility and potential group tactics suggest it had unusually advanced intelligence for a dinosaur.

Immortalized by "Jurassic Park," Velociraptor was more petite than its Hollywood portrayal but no less deadly. Weighing around 15 kilograms (33 pounds), it had a relatively small size but a bigger brain compared to most other dinosaurs.

It also had hollow bones and walked on two powerful hind legs. Its curved claws and agile body complemented complex hunting strategies and quick attacks. Some scientists suggest that it may have hunted in packs.

This so-called "egg thief" has gotten a bad rap. The name "Oviraptor" comes from the Greek words for "egg" and "thief," but later fossil finds revealed that it was likely guarding its own nest. That’s not thievery; it’s parental care.

Living during the Late Cretaceous, Oviraptor had a relatively large brain and birdlike features, including a beak and crest. It showed behaviors that point to higher intelligence, like nesting (aka brooding).

Sometimes called the "ostrich mimic," Ornithomimus had a lightweight frame and strong legs, like a modern ostrich. Its brain size was larger than average for dinosaurs of its class.

It lived during the Late Cretaceous period and likely used its speed and smarts to avoid predators. Some fossilized remains even suggest feathered bodies and birdlike behaviors.

The name "Maiasaura" means "good mother lizard," and fossil nests show evidence of parental care. This herbivore from the Late Cretaceous lived in large herds, possibly to protect young from predators.

While not a predator, Maiasaura had a brain capable of complex social behavior, which suggests intelligence beyond simple survival instincts.

Known for its thick, domed skull, Pachycephalosaurus also had a larger-than-expected brain cavity that reveals it had excellent eyesight and a well-developed sense of smell. It lived in the Late Cretaceous period and may have engaged in social or competitive behaviors.

Its intelligence isn’t as well-studied as that of carnivorous species, but brain volume and body structure hint at strategic or ritualistic combat.

A large herbivore from the Early Cretaceous period, Iguanodon was one of the first dinosaurs discovered. It had a modestly sized brain for its body but used its hind legs and thumb spikes for defense.

Iguanodon may have displayed herd behavior and had a level of coordination that required communication among members.

T. rex, the apex predator of the Late Cretaceous, had a large brain but also a massive body. While smart for a dinosaur of its size, its brain-to-body ratio was low.

Still, T. rex had a keen sense of smell, powerful legs, and keen sensory abilities (depth perception and smell) that aided in hunting prey. Some fossil finds even suggest it may have hunted in pairs or small groups, hinting at modest cognitive abilities.

We created this article in conjunction with AI technology, then made sure it was fact-checked and edited by a HowStuffWorks editor.