(Btw everything I write here about orcas also applies to a slightly lesser extent to pilot whales (especially long finned ones)[1].)
(I’m very very far from an orca expert—basically everything I know about them I learned today.)
I always thought that bigger animals might have bigger brains than humans but not actually more neurons in their neocortex (like elephants) and that number of neurons in the neocortex or prefrontal cortex might be a good inter-species indicator of intelligence for mammalian brains.[2] Yesterday I discovered that orcas actually have 2.05 times as many neurons in their neocortex[3] than humans from this wikipedia list. Interestingly though, given my pretty bad model of how intelligent some species are, the “number of neurons in neocortex” still seems like a proxy that doesn’t perform too badly on the wikipedia list.
Orca brains are not just larger but also more strongly folded.
Orcas are generally regarded as one of the smartest animal species, sometimes as the smartest, but I’m wondering whether they might actually be smarter than humans—in the sense that they could be superhuman at abstract problem solving if given comparable amounts of training as humans.
Another phrasing to clarify what I mean by “could trained to be smarter”: Average orcas significantly (possibly vastly) outperforming average (or even all) humans at solving scientific problems, if we enabled them to use computers through BCI and educated them from childhood like (gifted?) human children.[4]
I would explain the evidence and considerations here in more detail but luckily someone else already wrote the post I wanted to write on reddit, only a lot better than I could’ve. I highly recommend checking this out (5min read): https://www.reddit.com/r/biology/comments/16y81ct/the_case_for_whales_actually_matching_or_even/
One more thing that feels worth adding:
Orcas are very social animals.[5] It’s plausible to me that what caused humans to become this intelligent were social dynamics selecting for intelligence[6], and that orcas might’ve fallen into a similar attractor, and while humans took off technologically once they were smart enough to invent writing, agriculture, money and science, orcas were stuck without hands in water and just continued being selected for higher intelligence without taking off technologically.
I’d be interested in more thoughts and evidence, so please feel free to write an answer even if you don’t have an answer but only one more interesting piece of evidence or consideration to contribute.
- ^
Also possible there are more animals/dolphins/whales for which this applies. We often don’t have good estimates on how many neurons are in a neocortex of some animal.
- ^
It could be that animals with larger bodies need more neurons to be similarly intelligent as smaller animals (e.g. for body control), but I think this effect is relatively slight.
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I didn’t quickly find something on what share of the orca brain is prefrontal cortex.
- ^
Btw I could imagine that even if they were able to do so they might not be motivated for it because maybe evolution had longer time to more precisely align them to do what’s reproductively useful in their natural environment or sth.
- ^
Btw here’s a reddit comment (from a different thread than the main one I linked) linking to 3 references that seem relevant, though I didn’t check them: https://www.reddit.com/r/orcas/comments/18yu41m/comment/lriv011/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button
- ^
Some of my own observations and considerations:
Anecdotal evidence for orca intelligence
Intimate cooperation between native australian hunter gatherers and orcas for whale hunting: https://en.wikipedia.org/wiki/Killer_whales_of_Eden,_New_South_Wales
Orcas being skillful at turning boats around and even sinking a few vessels[1][2]: https://en.wikipedia.org/wiki/Iberian_orca_attacks
Orcas have a wide variety of cool hunting strategies. (e.g. see videos (1, 2)). I don’t know how this compares to human hunter gatherers. (EDIT: Ok I just read Scott Alexander’s Book review of “The Secret of our success” and some anecdotes on hunter gatherers there seem much more impressive. (But also plausible to me that other orca hunting techniques are also more sophisticated than the examples but in ways it might not be legible to us.))
(ADDED: Tbc, while this is more advanced than I’d a priory expected from animals, the absence of observations of even more clearly stunning techniques is some counterevidence of orcas being smarter than humans. Though I also don’t quite point to an example of what I’d expect to see if orcas were actually 250 IQ but what I don’t observe, but I also didn’t think for long and maybe there would be sth.)
Orca language
(Warning: Low confidence. What I say might be wrong.)
I didn’t look deep into research into orca language (not much more than watching this documentary), my impression is that we don’t know much yet.
Some observations:
Orcas language seems to be learned, not innate. Different regions have different languages and dialects. Scientists seem to analogize it to how humans speak different languages in different countries.
For some orca groups that were studied, scientists were able to cluster their calls into 23 or 24 different calls clusters, but still with significant variation of calls within a call cluster.
(I do not know how tightly calls are clustered, or whether there often are outliers.)
Orcas communicate a lot. (This might be wrong but I think they spend a significant fraction of their time socializing where they exchange multiple calls per minute.)
(Orcas emit clicks and whistles. The clicks are believed to be for spacial navigation (especially in the dark), the whistles for communication.) (EDIT: Actually also pulsed calls, which I initially lumped in with whistles but are emitted in pulses. Those are probably the main medium of communication.)
I’d count (2) as some weakish evidence against orcas having as sophisticated language as humans, however not very strongly. Some considerations:
Sentences don’t necessarily need to be formed through having temporal sequences of words, but words could also be some different frequency signals or so which are then simultanously overlayed.
(The different 24 call types could be all sorts of things. E.g. conveying what we convey through body language, facial expressions, and tone. Or e.g. different sentence structures. Idk.)
Their language might be very alien. I only have shitty considerations here but e.g.:
Orca language doesn’t need to have at all similar grammar. E.g. could be something as far from our language as logic programming is, though in the end still not nearly that simple.
Orcas might often describe situations in ways we wouldn’t describe them. E.g. rather about what movements they and their prey executed or sth.
Orcas might describe more precisely where in 3D water particular orcas and animals were located, and they might have a much more efficient encoding for that than if we tried to communicate this.
More considerations
The only piece of evidence that makes me wonder whether orcas might actually be significantly smarter than humans is their extremely impressive brain. I think it’s pretty strong though.
As mentioned, orcas have 2.05 times as many neurons in their neocortex as humans, and when I look through the wikipedia list (where I just trust measured[3] and not estimated values), it seems to be a decent proxy for how intelligent a species is.
There needs to be some selection pressure for why they have 160 times more neurons in their neocortex than e.g. brown bears (which weigh like 1/8th of an orca or so). Size alone is not nearly a sufficient explanation.
It’s plausible that for both humans and orcas the relevant selection pressure mostly came from social dynamics, and it’s plausible that there were different environmental pressures. (I’m keen to learn.) It’s possible that caused humans to be smart more strongly incentivized our brains to be able to do abstract reasoning, whereas for orcas it might’ve been useful for some particular skills that generalize less well for doing other stuff.
If I’d only ever seen hunter gatherer humans, even if I could understand their language, I’m not sure I’d expect that species to be able to do science on priors. But humans are able to do it. Somehow our intelligence generalized far outside the distribution we were optimized on. I don’t think that doing science is similar to anything we’ve been optimized on, except that advanced language might be necessary.
On priors I wouldn’t really see significant reasons why whatever selection pressures optimized orcas to have their astounding brains, would make their intelligence generalize less well to doing science, than whatever selection pressures produced our impressive human brains.
One thing that would update me significantly downwards on orcas being able to do science is if their prefrontal cortex doesn’t contain that many neurons. (I didn’t find that information quickly so please lmk if you find it.) Humans have a very large prefrontal cortex compared to other animals. My guess would be that orcas have too, and that they probably still have >1.5 times as many neurons in their prefrontal cortex than humans, and TBH I even wouldn’t be totally shocked if it’s >2.5 times.
Btw there is no recorded case of a human having been killed by an orca in the wild, including when they needed to swim when the vessel was sunk. (Even though orcas often eat other mammals.) (I think I even once heard it mention that it seemed like the orcas made sure that no humans died from their attacks, though I don’t at all know how active the role of the orcas was there (my guess is not very).)
I’d consider it plausible that they were trying to signal us to please stop fishing that much, but I didn’t look nearly deeply enough into it to judge.
Aka optical or isotropic fractionator in the method column.
Another thought:
In what animals would I on priors expect intelligence to evolve?
Animals which use collaborative hunting techniques.
Large animals. (So the neurons make up a smaller share of the overall metabolic cost.)
Animals that can use tools so they benefit more from higher intelligence.
(perhaps some other stuff like cultural knowledge being useful, or having enough slack for intelligence increase from social dynamics being possible.)
AFAIK, orcas are the largest animals that use collaborative hunting techniques.[1] That plausibly puts them second behind humans for where I would expect intelligence to evolve. So it doesn’t take that much evidence for me to be like “ok looks like orcas also fell into some kind of intelligence attractor”.
Though I heard sperm whales might sometimes collaborate too, but not nearly that sophisticated I guess. But I also wouldn’t be shocked if sperm whales are very smart. They have the biggest animal brains, but I don’t whether the cortical neuron count is known.
A few more thoughts:
Actually my guess would be that it’s because intelligence was environmentally adaptive, because my intuitive guess would be that group selection[1] is significant enough over long timescales which would disincentivize intelligence if it’s not already (almost) useful enough to warrant the metabolic cost, unless the species has a lot of slack.
So an important question is: How adaptive is high intelligence?
In general I would expect that selection pressure for intelligence was significantly stronger in humans, but maybe for orcas it was happening over a lot longer time window, so the result for orcas could still be more impressive.
From what I observed about orca behavior I’d perhaps say a lower bound of their intelligence might roughly be like human 15 year olds or so. So up to that level of intelligence there seem to be benefits that allow orcas to use more sophisticated hunting techniques.
But would it be useful for orcas to be significantly smarter than humans? My prior intuition would’ve been that probably not very much.
But I think observing the impressive orca brains mostly screens this off: I wouldn’t have expected orcas to evolve to be that smart, and I similarly strongly wouldn’t have expected them to have that impressive brains, and seeing their brains updates me that there had to be some selection pressure to produce that.
But the selection pressure for intelligence wouldn’t have needed to be that strong compared to humans for making the added intelligence worth the metabolic cost, because orcas are large and their neurons make up a much smaller share of their overall metabolic consumption. (EDIT: Actually (during some (long?) period of orca history) selection pressure for intelligence also would’ve needed to be stronger than selection pressure for other traits (e.g. making muscles more efficient or whatever).)
And that there is selection pressure is not totally implausible in hindsight:
Orcas hunt very collaboratively, and maybe there are added benefits from coordinating their attacks better. (Btw, orcas live in matrilines, and I’d guess that from an evolutionary perspective the key thing to look at is how well a matriline performs, not individuals, but not sure. So there would be high selection for within-matriline cooperation (and perhaps communication!).)
Some/(many?) Orca sub-species prey on other smart animals like dolphins or whales, and maybe orcas needed to be significantly smarter to be able to outwit the defensive mechanisms they learn to adapt.
But overall I know way too little about orca hunting techniques to be able to evaluate those.
I mean group selection that could potentially be on a level of species where species go extinct. Please lmk if that’s actually called differently.