Smart birds hint at very clever dinosaur ancestors

Current (and lowest common) thinking is that dinosaurs were dumb, despite living and evolving for 165-180 million years in the not exactly user-friendly environs that was the Mesozoic era. 

This thinking neglects to add that long, looong after those after-effects of a big meteor had wiped out the big 'uns, their tiny, obviously very intelligent, problem-solving, song-making, sentient-proven avian survivors added another ~60 millions years, which they continue to do to this day. 

And yet, the smarter ones among us always hubristic Homo sapiens types like to think we mammals have the monopoly on brainpower, as testified by the very cute song above and introduction below:

"There is a reason why dinosaurs were big and strong, but not that smart. It has to do with their metabolic system and how it was hampered by the high CO2 levels during the Mesozoic." Ugo Bardi of the Seneca Effect expands on his idea on substack.

My 5-cents worth reply:

'tis with much trepidation that I pit my by now obviously O2-starving brain into the mix but my first q, how do we know that dinos were dumb? 

Second, how do we measure smart? 

One of my daily joys is hearking the tiny jazz improvs of a wee dino offspring called the Cape Robin, down south in Africa. Like our screams of hadidas, they flit along their territories to mark borders and determine pecking orders in song battles. 

Just listen to this typical Cape Robin Chat sing, imitate and scold, and this is at half the pace of its much more energetic efforts during the dawn chorus.

 

Each Cape robin's song is ~2 seconds long, one starting note followed by three notes, thrills or florishes, each 2-second song unique. Day and night, 100s of improfs, not just random noises mind, but quite beautiful little musical creations. This from a bird with a brain < a pea. 
As said, 'tis with trepidation that I proffer this, but when it comes to parsing thought, the recent hypotheses presented by morphic resonance; knowledge as an entity; brains as tuning knobs for alternative realities; and languages as symbiotic parasatises; may be better trees to bark up than viewing the gas of life, aka CO2, as a stupifier.

And Ugo's answer:

A pleasure to answer you, Alwyn. Dinosaurs were not really dumb, but they were limited in terms of "encephalization quotient" (EQ). A corrected measure of the ratio of the brain weight to body weight. An approximation, but it does tell us something -- in most cases, the EQ of dinosaurs is way below that of modern birds and mammals. Actually, Suzana Herculano-Houzel thinks a T-rex could have been as intelligent as a baboon, but, honestly, she seems to me a little optimistic.

I know it hurts, because I am a dinosaur lover -- just like you, I think. But it is like this. Dinosaurs couldn't sustain big brains because high CO2 concentrations slowed down the energy production in brain cells. They had the same kind of brain engine we have, but their "fuel" didn't have the same power as the one we have now.

About your Cape Robin, it is a modern dinosaur. It surely has a higher EQ than its ancestors because it breathes a different air.

Finally, in terms of stupefiers, we have a large choice. CO2 is one of them. Possibly there are much more important ones, but CO2 is one that cannot be controlled. We have no control on the composition of the air we breathe.