Why didn't the dinosaurs evolve intelligence?

The dinosaurs, with all the variety of species, where around for 300 million years and most of their brains were the size of a pea. Man has been around for considerably less… Does this mean we have stopped evolving physically?

To some degree we have not stopped evolving but have skewed it. Remember in strict evolutionary terms what doesn’t work - dies. What does work - thrives. This isn’t exactly the case with humans anymore

People with medical conditions that would have died out without reproducing (to pass on those so called defective genes) are now living, through medical intervention, to reproduce and pass on genes.

But to some degree people are evolving still, but it takes Millions of cycles of birth and death to notice even subtle changes. However humans, once again through medical intervention, are changing that. For instance certain nationalities are becoming taller, the Japanese for one, (but that is due to better nutrition more or less) than they were (on average) 300 years ago.

I’m having a bit of trouble following your premises here. Do you mean since dinosaurs were around for so “long” they should have developed intelligence?

Any number of organisms have been around as long as or longer than the dinosaurs, but none of them have developed intelligence either. I happen to think the physiologically expensive proposition of a big brain and the ability to “think” is a distinct evolutionary disadvantage that will disappear in the blink of an eye, epoch-wise. That leaves the opossums, cockroaches and microbes to celebrate the 10 millionth anniversary of the government’s attack on the Branch Davidians at Waco.

Well, a few things come to mind.

  1. LOTS of species have been around a lot longer than humans, and never developed our intelligence. Why single out dinosaurs? You might as well ask, “Why haven’t opossums developed intelligence?” The best answer is, IF you accept the basic Darwinian model, the traits that endure are those that help a species to survive (or, at the very least, do no harm).

Example: Would a powerful brain help a cow very much? No… all a cow has to do to survive is munch on grass, run from predators, and (occasionally) migrate to where there’s food and water. It’s not so much that cows are stupid- it’s more that stupidity isn’t a real drawback to cows! Their needs are simple, so simple that even a stupid cow can do the things it must to survive. For such animals, stupidity is not an evolutionary disadvantage, so there was no reason for cows to develop intelligence. The same may well be true for most of the vegetarian dinosaurs.

  1. Intelligence is relative. How do we know how intelligent dinosaurs were, and compared to what? In general, intelligence is measured in terms of the ability to solve problems and the ability to learn. By these standards, most reptiles are not intelligent at all. But new evidence suggests that dinosaurs were very different from modern reptiles, so… who knows? They MAY have been more intelligent than the old “pea brain” model allowed.

An interesting question. But I want to know why do you make the assumption that dinosaurs were not intelligent? Intelligence is measured in many ways. The fact that dinosaurs didn’t write or construct buildings doesn’t mean that they didn’t develop the ability communicate (which denotes intelligence in my book).

Astorian notes:

Or, better yet: Why haven’t humans developed wings?

The original question picked out one attribute among millions. Sure, wings are great for birds (well, most of 'em), but that doesn’t mean they would suit humans well.

One factor is that animal life as a whole seems to have a slow evolutionary trend toward higher intelligence. Even leaving humans out, the average critter today is significantly smarter than the average Tertiary critter, who was smarter than the average dinosaur. (At least, as far as we can determine from brain-to-body ratios.)

Note that sustaining a powerful brain takes a lot of metabolic investment.

John W. Kennedy
“Compact is becoming contract; man only earns and pays.”
– Charles Williams

Didn’t you see the raptors in Jurassic Park? They were way smart!

“non sunt multiplicanda entia praeter necessitatem”
– William of Ockham

Although Jurassic Park is of course fictional, it has been pointed out that crows and parrots seem to be pretty smart at least as far as birds go, and they don’t have very big brains.

Why didn’t

“WE DID!!!”–Mr. G. Zilla of Tokyo, Japan

Brain-to-body ratio is, as a rule, a much better indication of intelligence than brain alone.

John W. Kennedy
“Compact is becoming contract; man only earns and pays.”
– Charles Williams