Could a human level intelligence species evolve in the oceans?

Everything that our anatomy and environment allows, as a moment’s reflection will reveal. Human intelligence is an evolutionary adaptation to our unique environment. Dolphins are smart because they once lived on land and became sea creatures. Animals that did not (fish) do not approach marine mammals in intelligence. You should not use marine mammals as an example, because they are kind of an oddity. They acquired their intelligence on land, thus proving my point. QED

If humans took to the sea, we could keep what we had if it proved useful, but it would still be legacy intelligence, not “evolved in the oceans”.

The most intelligent ocean-dwelling creatures are mammals that did not evolve in the oceans. Dolphins and other cetaceans gradually adapted to aquatic life over millions of years after being terrestrial creatures (mammals).

DHA from marine sources played a critical role in the evolution of primate and later human intelligence.

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Human level intelligence evolved because there was the ocean to offer nutrients to support a large and complex brain. It is certainly possible that a marine species could develop a similar level of intelligence. Maybe dolphins will become superintelligent if we leave them alone for 500 million years.

I can imagine dolphins learning to raise and herd livestock. Possibly even enslaving or domesticating beneficial species.

In a sci-fi book I recently read, which I forgot the title, it was opined that intelligent (human like) life usually happens for one species on a planet and that is a rare event. If that happens to be a water based species that is most likely a dead end as it would be almost impossible for them to develop spaceflight and therefor would never be able to leave their planet and would eventually die there when their planet suffers such a major catastrophe or their star fails them.

If macroscopic life can evolve in an environment I don’t see a reason why intelligence couldn’t. Earth’s oceans are prosaic compared to theorized environments on other planets.

Yeah but it doesn’t follow that the period of living on land was the crucial factor. After all, dolphins have had to evolve a number of mental abilities* since being in the sea – presumably they did not have echolocation on land.
The reason fish don’t have the smarts may be because of energy and oxygen requirements; the mammalian physiology is better suited to supporting an energy-intensive organ and maintaining it’s homeostasis.
Or it might just be dumb luck; general intelligence just happened to get its start in mammals and the difference has snowballed ever since.

  • FTR, I am not one of the “Dolphins are virtually as smart as humans” brigade.
    For any reasonable definition of “smart” the gap between humans and any terrestrial species is vast.
    (And no, “reasonable definition” doesn’t mean making iPods. It means solving novel problems).

Please answer the question in Post #10.

Can someone offer please a working defintion of intelligence (preferably with some metric attached) that could be used for interspecies comparisons, one does not define intelligence as that which modern humans do.

The best I have ever heard is the ability to solve novel salient problems, with the nature of what is salient defining different sorts of intelligence.

Is that acceptable? If not what is? Is intelligence like porn: we are supposed to know it when we see it?

Clearly the intelligence to process information about a variety of complex social, prey, and predetor actors in a huge volume of space and to solve problems related to them is something that whales have to a great degree and we do not. Clearly whale level intelligence can not develop on the land (as a whale would define it).

Why not?

I’d say a human-level intelligence could develop purely in the ocean, in some cephalopod species, but IMO only if they somehow changed from an r-selection to a K-selection reproductive strategy and had drastically increased lifespans.

They’ll never develop human-level technology in the sea, though. Fire is a must, there.

Interesting; I wonder if the lack of fire is a complete roadblock to higher level technology. Now that I think about this question I don’t think an intelligent sea species would even be able to leverage animal labor the way we did, or form an agricultural society. I guess there may be fitting alternatives for the sea, but that’s beyond my ability to fathom.

O R’LYEH?
(Well, someone had to)

I think that’s the point, that an aquatic equivalent of intelligence wouldn’t look a great deal like ours.

Of course it does. Where are all the ‘smart’ fish?

According to Wikipedia, cetaceans diverged from their common ancestor with hippopotami (who AFAIK are not particularly intelligent) about 55 million years ago, and became marine mammals 50 million years ago. If their intelligence developed on land was it during that relatively brief 5 million year period? I think it’s more likely they developed intelligence because of the influence of their ocean environment.

I think all mammals are smarter than other amniotes, and all amniotes are smarter than fish, no? To satirize your argument I could write, “if intelligence develops on land, where all the smart earthworms?”

Terrestrial life has different demands than marine life. It requires much more sophisticated sensory and intellectual abilities.

From Nietzsche, On The Genealogy Of Morals.

At this juncture I suppose that a tentative and provisional
expression of my own hypothesis concerning the origin of ‘bad
conscience’ must be offered; yet it is not something easily put
forward, and it requires prolonged, careful consideration on the
part of the reader. I regard bad conscience as a serious illness to
which man was bound to succumb under the stress of the most
radical change which he has ever experienced – the change
which occurred when he found himself finally imprisoned by
the strictures imposed upon him by society to establish and preserve
peace. Just as it was with marine animals, when they were
compelled to become terrestrial animals if they were to survive
at all, so must it also have been with these savages, perfectly
adapted as they were to the wilderness, to war, to a nomadic
existence, and to exploration – suddenly all their instincts were
rendered useless. From that time forwards they had to walk on
their feet, and were no longer borne by the water; their own
weight, which they now had to bear, oppressed them. They felt
inept and were unable to perform the simplest tasks; confronted
with this new and unknown world they no longer could rely
upon their old guides, the regulative, unconscious instincts which
had kept them safe; they were reduced, those miserable creatures,
to thinking, inferring, calculating, to connecting cause and
effect, and had to resort to using their most poorly developed,
least reliable organ, their ‘consciousness’. I do not believe there
was ever in the history of the world such a feeling of misery, such
an intense discomfort – and furthermore, those old instincts had
not suddenly ceased making their demands!

That is one of the biggest leaps of non-logic I’ve ever seen…and I argue regularly with creationists.

Nietzsche was a biologist? Who knew?

Because the novel problems of salience are very different. Our intelligence can not even comprehend what sort of problems they are.

Personally I am of the belief that individual humans are not so intelligent; it is the meta-organism of human culture and society, the ability of these limited brains to work together including across multiple generations, that is so intelligent. Writing and technology did nothing for intelligence (the capacity) of the individual human, but it allowed for that meta-organism to come into being and to thrive.