I disagree with most of this. Modern Animals are much smarter than we previously thought. I would say that sauropods and large mesozoic herbivores were about as smart as the large herbivores alive today. Rhino-smart. Maybe even elephant level for some. Large Jurassic theropods would be maybe as smart as a lion, or in some cases a crocodile. Raptors would be as smart as the smartest birds. Which is pretty damn smart.


Dinosaurs weren't totally mindless, but they weren't unprecedented geniuses either like how Jurassic Park portrays some of them. Its impossible to jump inside the head of an animal and see what they are thinking, let alone one that has been dead for millions of years. However by studying the skulls of dinosaurs, the size of the braincase can be compared to the size of the skull to determine a ratio known as an encephalization quotient. The higher the number, the larger the braincase is in relation to the size of skull and the more intelligent that animal was likely to have been. When discussing dinosaurs, there are two systems used: REQ (reptile encephalization quotient) and a modified version known as BEQ (bird encephalization quotient). Estimated REQs, based off of studying skulls of sauropod dinosaurs, indicate that some of the macronarian sauropods probably had an intelligence close to that of many modern day turtles, lizards, & snakes. For example *Camarasaurus* has an estimated REQ of 0.65, *Giraffatitan* has an estimated REQ of 0.66, the modern-day *Boa constrictor* snake has an REQ of 0.45, and the modern-day green sea turtle has an REQ of 0.89. Some sauropods, especially the members of the diplodocidae, were probably quite a bit less intelligent than even that, with *Apatosaurus* having an REQ only around 0.30. While the more intelligent sauropods weren't mindless and may have had some basic level of thought, they definitely weren't doing college math. In terms of the theropod dinosaurs, some of the more "advanced" coelurosaurs such as oviraptorosaurs like *Citipati* (estimated estimate BEQ of 0.34) and troodontids like *Troodon* (estimated BEQ of 0.97) were probably close in intelligence to some modern day birds such as the domestic chicken (BEQ of 0.32), the common ostrich (BEQ of 0.36), or the mallard duck (BEQ of 1.14) . Some of the larger theropods like *Tyrannosaurus* (estimated REQ of 0.45/BEQ of 0.12), *Allosaurus* (estimated REQ of 1.47/BEQ of 0.11) and *Carcharodontosaurus* (estimated REQ of 0.97/BEQ of 0.07) were probably closer in intelligence to something like the green iguana lizard (REQ of 0.92) or the American alligator (REQ of 0.77). These figures/stats I used all come from this book. I highly recommend reading it for more information this subject: [https://www.amazon.com/Dinosaur-Facts-Figures-Theropods-Dinosauriformes/dp/0691180318](https://www.amazon.com/Dinosaur-Facts-Figures-Theropods-Dinosauriformes/dp/0691180318)


That was really insightful! Thank you for the comment


I'm curious why do you think that dinosaurs were so unintelligent compared to modern animals?


I’m only basing this off what I’ve learned - and I know that sauropods and many groups of dinosaur plant eaters had extremely small brains in comparison to their bodies. Another commenter here did some research and found that an Sperm Whale has a brain 80 times larger than an Apatosaurus even though the two animals are about the same weight. But I don’t think dinosaurs were dumb at all, they were clearly very successful animals. Even if a sauropod had a similar intelligence to a fish (which is just a guess and I could stand to be corrected), a fish can still be a surprisingly intelligent animal in many ways. In regards to T. Rex, I remember reading an article that said that palaeontologists estimated its intelligence to be just outside of the reptilian spectrum and heading towards a more avian intelligence. It was an article explaining the faults in the theory that T. Rex was as smart as a chimp. And it’s largely thought to be one of the most advanced large theropod dinosaurs, a product of many years of evolution. And since Dromaeosaurs were supposedly some of the most intelligent dinosaurs, I thought it was safe to assume they’d be about as smart as a bird. Anyways that was my reasoning, but once again this was moreso me just throwing my guesses out there and hoping to get more educated answers to correct them.


So do you think that maybe, due to their brain size, that the dumber, bigger dinosaurs like sauropods might have had some sort of neural net that dealt with most of the animals reactions instead of having to be sent to the brain and then back, which would induce quite a lag time


So. Can a raptor open a door ?


Dinosaur intelligence is an interesting topic, but sadly we don't know enough to assume much


to follow up on this subject what about the intellgence of pterosaurs and marine reptiles like Mosasaurs and Icythosaurs?


Tyrannosaurus lived 30+ years and hunted cooperatively. Smarter than Bears I bet.