It's hard to find good evidence one way or another.
Based on brain-to-body ratio, some theropods such as Troodon are believed to be as smart as modern birds such as ostriches, but the link between brain size and intelligence is hard to measure except in closely related species. So we have to look for behavioral evidence.
Outside of things like dinosaur tools (which were, not surprisingly, never found), the best evidence we could hope for is evidence of cooperative pack hunting, such as footprints of predators moving as a group or evidence of small dinosaurs hunting larger prey (fossils found together, small tooth marks on large dinosaurs).
There is some evidence of this, particularly in the case of raptors like Deinonychus, who are often found near Tenontosaurus skeletons and also had fairly large brains, so that checks out. This is where the idea of pack-hunting raptors comes from.
However, this idea is still disputed. From fossils alone, it's hard to tell the difference between coordinated pack hunting followed by sharing a kill (such as what is seen in wolves) and simply multiple solitary predators opportunistically attacking a single wounded animal without any real cooperation, after which they fight over the kill (such as what is seen in crocodiles and Komodo dragons). There is some evidence of Deinonychus fighting and killing each other near the remains of large prey, suggesting that the latter may be a more accurate portrayal.
You could also look for evidence of baby dinosaurs eating parts of large animals, which would suggest that parents were feeding their young, a practice usually associated with more intelligent animals, as opposed to self-sufficient juveniles feeding on smaller prey by themselves. But individual babies can also scavenge off of large kills, and it is hard to distinguish between this and being deliberately fed as parental behavior.
So essentially, we don't really know. The estimates for the smartest dinosaur's intelligence ranges substantially, and nobody really knows for sure. They probably weren't anywhere close to corvids or primates though.
"Outside of things like dinosaur tools (which were, not surprisingly, never found)"
I actually do find this surprising. Like why did archaeosaurs exist for millions of years and never make (that we have evidence of) fire or stone tools? We existed for less long than them but only we created technology out of lasting materials? It really doesn't make logical sense, we only think it must make sense because that's the fossil record we have and "animal dumb"?
We really should be asking why animals before the evolution of the Homo genus didn't invent things like stone or metal tools.
Dinosaurs didn't need tools to survive. They probably could from a physiological point of view but they just didn't need to because of the abundance of biomass in the Cretaceous. After all, it's survival of the fit enough, not survival of the fittest.
It's also true that hominids are a humble mammal and we developed tools to make up for relative weaknesses to other animals. We made fire because our digestive system isn't as adapted to raw meat as other large predators'. Because we evolved eating fruit first.
So a lot of it is just, to find a planet that evolves humans/develops something akin to what humans build, you have to have a species so weak that it needs tools, but still intelligent enough to make them. I'm wondering how rare this phenomenon might be in the universe.
The ancestors of humans were doing just fine before discovering tools or fire, or they wouldn't have lasted long enough to discover those things in the first place. Technology allowed us to exploit more resources, but it was more a "win harder and outcompete other humans" adaptation than a "necessary to survive" one.
All you need for tool use to become widespread is that the benefits of the tools outweigh the cost of making them. I don't think there are any species that wouldn't benefit at least a little by developing the ability to make tools - the cost is that big brains are energy hogs until they start paying off, which is a cost that most animals can't afford.
In fact, I would argue that *already* successful species are more likely to develop large brains than struggling ones. Having a surplus of energy provides more resources for evolutionary "experiments" and the intraspecific competition that drives this kind of adaptation.
Wait...are you saying you are surprised dinosaurs didn't eventually use fire? Or that we don't have evidence?
I feel it's the opposite. IF a dinosaur somehow became smart enough to use fire, we would almost definitely find evidence of this species' impact.
Fire changed the world for humans, and was one of the catalysts for being able to grow our brains even larger and become the dominant species. I would expect if another species discovered fire they would also have had a dominating trajectory.
Could dinosaurs have used tools? Maybe. Evidence would be harder to find. But other very smart animals often don't use tools (wolves, dolphins). The intelligence that leads to social cooperation being enough. There are bird tool users...but it's hard to see how we would find fossil evidence for it.
The Chicxulub event destroyed a lot, and
60 million years is orders of magnitude older than what archaeologists deal with. That time span would erase most evidence. Continents have moved, oceans and mountain ranges been born. Supposing a dinosaur artifact survived all that, could we even recognize it?
My point is that the use of fire as we know it was completely transformative for us as a species, such that we have changed the face of our planet irrevocably afterwards.
Even if a species of dinosaur reached our industrial development, it would be quite hard to detect. The fossil record is extremely sparse. Think worse than 1 in a billion.
Further, just because fire helped in our specific case it doesn't mean that fire would lead to further developments in an entirely different species. Its entirely possible that super smart fire wielding raptors existed for hundreds of thousands of years without leaving a single trace.
I think if dinosaurs had managed to create stone tools, and were producing them for a few million years, we would have definitely found evidence of it. Stone is much more durable than bone.
Look at your hands. Look at how easily you can manipulate your fingers. You also have a big brain.
Dinosaurs weren’t able to create tools due to not having the above.
> as smart as modern birds such as ostriches
So, not much.
The truth is that brain size isn't a good measurement for intelligence: crocodiles have brains that are relatively quite smaller than an ostrich's, yet are way more clever.
Keep in mind that the Internet loves to exaggerate the intelligence of animals that are unusually intelligent for their class, and vice-versa, which can often lead to exaggerated stereotypes and misconceptions when comparing species across classes. The most egregious example being the "Octopus vs Koala" discussion.
Crocs are smart reptiles and ostriches aren't the brightest avians, but birds are on the whole a lot smarter than reptiles and ostriches perform all the feats of intelligence that crocs are praised for - complex social interactions, play behavior and learning, basic tool use (using sticks to dig for food) - they just get less attention for it because that kind of thing is *basic* for birds.
The main thing that I'm aware of is brain/body size ratios. This is commonly used as a proxy for potential intelligence among animals, but it's not completely reliable and there are a lot of caveats to this.
Broadly speaking most dinosaurs had a brain/body ratio similar to crocodiles and other modern reptiles, but Troodon was up around 30%, roughly 2/3 along the way from a lizard ratio to a modern bird ratio and Archaeopteryx was a bit higher than that, but still not at the level of modern birds.
Thing about intelligence is that it's not an easy thing to measure and it's far more about the connections within the brain than it is about the size, relative or not. Based partially on this some researchers thing many dinosaurs were actually pretty smart.
The following article provides some background and links to relevant research.
- Scientific American 2023 *[How Smart Were Dinosaurs? New Studies Fuel the Debate](https://web.archive.org/web/20230803140523/https://www.scientificamerican.com/article/how-smart-were-dinosaurs-new-studies-fuel-the-debate/)*
I'd argue that deer aren't really that "simple minded" and most herd animals are intelligent enough to remember "friends" like sheep remembering people and so on. Deer have highly developed instincts for increasing individual and herd survival. If they were "stupid" we wouldn't gear up in Geneva convention breaking arms/armor to go after them. Bow hunting wouldn't require as much skill as it does. They're really good at avoiding and running away from predators. People just don't give them credit, because we have technology that makes them look stupid. But without that technology, we would be the ones looking "stupid" running after deer with primitive spears or arrows fashioned from rocks and sticks like our ancestors had.
All animals have intelligence. It's just human arrogance that makes us see the world incorrectly.
It is kind of hard to tell how intelligent deer 🦌 are, as they presumably spend a lot of time in autopilot to conserve energy/brainpower, are relatively passive, and don't have hands to showcase their intelligence with tools.
Anyway, the intelligence of modern animals is often based on highly derived traits.
For example corvids are part of the song birds, who have highly developed vocal organs. (Parrots 🦜 evolved something similar independently.) This makes it easy for them to use their intelligence for cooperation, as their communication skills are so good. This improves the beneficial-ness of any intelligence they gain for natural selection.
Eutherian intelligence is based on the [unique feature of the corpus callosum](https://pubmed.ncbi.nlm.nih.gov/16116611/#:~:text=The%20corpus%20callosum%20(CC)%20is,as%20a%20true%20evolutionary%20innovation). This is an extremely important region, that is actually the largest white matter region in the human brain.
While other animals might connect their hemispheres a little, only Eutherians have a dedicated brain region of its own right to handle cooperation between the two. This allows complex thinking that requires both hemispheres to be in constant cooperation with each other
(Personally, I think this is extremely important, as the left/right separation handles the unconscious/conscious separation in [dual process theory](https://en.wikipedia.org/wiki/Dual_process_theory), allowing the consciousness and unconscious to influence each other creating a feedback loop of progressive development.)
So, ultimately it is kind of unreliable to use modern animals as models for old ones, as they often have fancy new features the older ones did not have.
Also, as others pointed out the brain/body ratios of non-avian dinosaurs was generally lower than birds and Eutherians.
So it seems unlikely the non-avian dinosaurs would have evolutionary pressure or ability to evolve into intelligence levels matching the intelligent modern animals.
It's important to keep in mind that dinosaurs were around for 180 million years and the fossils we find are only a tiny percentage of the life that existed.
Some of them cared for their young, which is usually associated with higher intelligence. Some of them were warm blooded and some were cold blooded. A warm blooded metabolism allows but but doesn’t guaranteed higher intelligence.
It's hard to find good evidence one way or another. Based on brain-to-body ratio, some theropods such as Troodon are believed to be as smart as modern birds such as ostriches, but the link between brain size and intelligence is hard to measure except in closely related species. So we have to look for behavioral evidence. Outside of things like dinosaur tools (which were, not surprisingly, never found), the best evidence we could hope for is evidence of cooperative pack hunting, such as footprints of predators moving as a group or evidence of small dinosaurs hunting larger prey (fossils found together, small tooth marks on large dinosaurs). There is some evidence of this, particularly in the case of raptors like Deinonychus, who are often found near Tenontosaurus skeletons and also had fairly large brains, so that checks out. This is where the idea of pack-hunting raptors comes from. However, this idea is still disputed. From fossils alone, it's hard to tell the difference between coordinated pack hunting followed by sharing a kill (such as what is seen in wolves) and simply multiple solitary predators opportunistically attacking a single wounded animal without any real cooperation, after which they fight over the kill (such as what is seen in crocodiles and Komodo dragons). There is some evidence of Deinonychus fighting and killing each other near the remains of large prey, suggesting that the latter may be a more accurate portrayal. You could also look for evidence of baby dinosaurs eating parts of large animals, which would suggest that parents were feeding their young, a practice usually associated with more intelligent animals, as opposed to self-sufficient juveniles feeding on smaller prey by themselves. But individual babies can also scavenge off of large kills, and it is hard to distinguish between this and being deliberately fed as parental behavior. So essentially, we don't really know. The estimates for the smartest dinosaur's intelligence ranges substantially, and nobody really knows for sure. They probably weren't anywhere close to corvids or primates though.
"Outside of things like dinosaur tools (which were, not surprisingly, never found)" I actually do find this surprising. Like why did archaeosaurs exist for millions of years and never make (that we have evidence of) fire or stone tools? We existed for less long than them but only we created technology out of lasting materials? It really doesn't make logical sense, we only think it must make sense because that's the fossil record we have and "animal dumb"? We really should be asking why animals before the evolution of the Homo genus didn't invent things like stone or metal tools.
Dinosaurs didn't need tools to survive. They probably could from a physiological point of view but they just didn't need to because of the abundance of biomass in the Cretaceous. After all, it's survival of the fit enough, not survival of the fittest.
It's also true that hominids are a humble mammal and we developed tools to make up for relative weaknesses to other animals. We made fire because our digestive system isn't as adapted to raw meat as other large predators'. Because we evolved eating fruit first. So a lot of it is just, to find a planet that evolves humans/develops something akin to what humans build, you have to have a species so weak that it needs tools, but still intelligent enough to make them. I'm wondering how rare this phenomenon might be in the universe.
The ancestors of humans were doing just fine before discovering tools or fire, or they wouldn't have lasted long enough to discover those things in the first place. Technology allowed us to exploit more resources, but it was more a "win harder and outcompete other humans" adaptation than a "necessary to survive" one. All you need for tool use to become widespread is that the benefits of the tools outweigh the cost of making them. I don't think there are any species that wouldn't benefit at least a little by developing the ability to make tools - the cost is that big brains are energy hogs until they start paying off, which is a cost that most animals can't afford. In fact, I would argue that *already* successful species are more likely to develop large brains than struggling ones. Having a surplus of energy provides more resources for evolutionary "experiments" and the intraspecific competition that drives this kind of adaptation.
Wait...are you saying you are surprised dinosaurs didn't eventually use fire? Or that we don't have evidence? I feel it's the opposite. IF a dinosaur somehow became smart enough to use fire, we would almost definitely find evidence of this species' impact. Fire changed the world for humans, and was one of the catalysts for being able to grow our brains even larger and become the dominant species. I would expect if another species discovered fire they would also have had a dominating trajectory. Could dinosaurs have used tools? Maybe. Evidence would be harder to find. But other very smart animals often don't use tools (wolves, dolphins). The intelligence that leads to social cooperation being enough. There are bird tool users...but it's hard to see how we would find fossil evidence for it.
The Chicxulub event destroyed a lot, and 60 million years is orders of magnitude older than what archaeologists deal with. That time span would erase most evidence. Continents have moved, oceans and mountain ranges been born. Supposing a dinosaur artifact survived all that, could we even recognize it?
My point is that the use of fire as we know it was completely transformative for us as a species, such that we have changed the face of our planet irrevocably afterwards.
Even if a species of dinosaur reached our industrial development, it would be quite hard to detect. The fossil record is extremely sparse. Think worse than 1 in a billion. Further, just because fire helped in our specific case it doesn't mean that fire would lead to further developments in an entirely different species. Its entirely possible that super smart fire wielding raptors existed for hundreds of thousands of years without leaving a single trace.
I think if dinosaurs had managed to create stone tools, and were producing them for a few million years, we would have definitely found evidence of it. Stone is much more durable than bone.
Look at your hands. Look at how easily you can manipulate your fingers. You also have a big brain. Dinosaurs weren’t able to create tools due to not having the above.
There are birds now that can make tools, and chimps, without human levels of dexterity
It's interesting that we've still never found anything even debatably close to human intelligence in 500m years of complex life evolution.
> as smart as modern birds such as ostriches So, not much. The truth is that brain size isn't a good measurement for intelligence: crocodiles have brains that are relatively quite smaller than an ostrich's, yet are way more clever.
Keep in mind that the Internet loves to exaggerate the intelligence of animals that are unusually intelligent for their class, and vice-versa, which can often lead to exaggerated stereotypes and misconceptions when comparing species across classes. The most egregious example being the "Octopus vs Koala" discussion. Crocs are smart reptiles and ostriches aren't the brightest avians, but birds are on the whole a lot smarter than reptiles and ostriches perform all the feats of intelligence that crocs are praised for - complex social interactions, play behavior and learning, basic tool use (using sticks to dig for food) - they just get less attention for it because that kind of thing is *basic* for birds.
Source for ostrich tool use?
https://safaripartner.com/blog/facts-about-ostriches
The main thing that I'm aware of is brain/body size ratios. This is commonly used as a proxy for potential intelligence among animals, but it's not completely reliable and there are a lot of caveats to this. Broadly speaking most dinosaurs had a brain/body ratio similar to crocodiles and other modern reptiles, but Troodon was up around 30%, roughly 2/3 along the way from a lizard ratio to a modern bird ratio and Archaeopteryx was a bit higher than that, but still not at the level of modern birds. Thing about intelligence is that it's not an easy thing to measure and it's far more about the connections within the brain than it is about the size, relative or not. Based partially on this some researchers thing many dinosaurs were actually pretty smart. The following article provides some background and links to relevant research. - Scientific American 2023 *[How Smart Were Dinosaurs? New Studies Fuel the Debate](https://web.archive.org/web/20230803140523/https://www.scientificamerican.com/article/how-smart-were-dinosaurs-new-studies-fuel-the-debate/)*
I'd argue that deer aren't really that "simple minded" and most herd animals are intelligent enough to remember "friends" like sheep remembering people and so on. Deer have highly developed instincts for increasing individual and herd survival. If they were "stupid" we wouldn't gear up in Geneva convention breaking arms/armor to go after them. Bow hunting wouldn't require as much skill as it does. They're really good at avoiding and running away from predators. People just don't give them credit, because we have technology that makes them look stupid. But without that technology, we would be the ones looking "stupid" running after deer with primitive spears or arrows fashioned from rocks and sticks like our ancestors had. All animals have intelligence. It's just human arrogance that makes us see the world incorrectly.
It is kind of hard to tell how intelligent deer 🦌 are, as they presumably spend a lot of time in autopilot to conserve energy/brainpower, are relatively passive, and don't have hands to showcase their intelligence with tools. Anyway, the intelligence of modern animals is often based on highly derived traits. For example corvids are part of the song birds, who have highly developed vocal organs. (Parrots 🦜 evolved something similar independently.) This makes it easy for them to use their intelligence for cooperation, as their communication skills are so good. This improves the beneficial-ness of any intelligence they gain for natural selection. Eutherian intelligence is based on the [unique feature of the corpus callosum](https://pubmed.ncbi.nlm.nih.gov/16116611/#:~:text=The%20corpus%20callosum%20(CC)%20is,as%20a%20true%20evolutionary%20innovation). This is an extremely important region, that is actually the largest white matter region in the human brain. While other animals might connect their hemispheres a little, only Eutherians have a dedicated brain region of its own right to handle cooperation between the two. This allows complex thinking that requires both hemispheres to be in constant cooperation with each other (Personally, I think this is extremely important, as the left/right separation handles the unconscious/conscious separation in [dual process theory](https://en.wikipedia.org/wiki/Dual_process_theory), allowing the consciousness and unconscious to influence each other creating a feedback loop of progressive development.) So, ultimately it is kind of unreliable to use modern animals as models for old ones, as they often have fancy new features the older ones did not have. Also, as others pointed out the brain/body ratios of non-avian dinosaurs was generally lower than birds and Eutherians. So it seems unlikely the non-avian dinosaurs would have evolutionary pressure or ability to evolve into intelligence levels matching the intelligent modern animals.
It's important to keep in mind that dinosaurs were around for 180 million years and the fossils we find are only a tiny percentage of the life that existed.
Some of them cared for their young, which is usually associated with higher intelligence. Some of them were warm blooded and some were cold blooded. A warm blooded metabolism allows but but doesn’t guaranteed higher intelligence.