I totally agree that invoking humans here would have been useful! If the post hadn’t already been pushing 8000 words (and I didn’t have work to do on my master’s thesis lol) I probably would have done so!
In terms of why I think crows are grayer than humans, I think it’s because the assortive mating in crows is probably significantly more stable (and probably genetically determined) than assortive mating in humans. It’s true that humans do assortive mating, but it does not tend to be stable over anything approaching the geological time that is (usually) required for speciation. The Casta system in South America is a good example -- 350 years of legally enforced, super racist assortive mating that lasted for many generations, but eventually collapsed and now South America is one big intermingled, intermarried population. Interracial marriage statistics in the US are another example—they were insanely low before the 1950s, but have risen substantially since then as cultural mores changed, which is over only like 80 years. Social divisions from only like 1,000 or 2,000 years ago seem absolutely absurd to us now. Spartans being forbidden to. marry helots, for example. Nobody in modern day Greece has such a distinction. Because they all ended up interbreeding, despite assortive mating preferences and laws etc.
that whole time, the hooded crows and the carrion crows have been assortive mating. They’ve probably been doing so for a very long time, tens of thousands of years. This indicates that either 1) it’s very genetic, and relatively stably so, or 2) that crow “culture” (which does exist, can be seen in mating structure differences around Europe, though it’s obviously not comparable to human culture in extent) is also extremely stable. My guess is that it’s genetic, but I suppose both are possible.
In both these ways, this assortive mating looks different to evolution (and thus speciation) than human assortive mating. Since it’s so stable with these crows, we can say with (relatively) high certainty that these two populations will speciate along these precise lines, and probably very soon. We cannot say such a thing about any two populations of human with any certainty, because human culture and migration and history is so contingent and unstable.
I still don’t think this is a reason to split the crows. I stand by them being different species. This is just why I empathize with people who say they should be different species. They’re probably about to become them.
Hey, Ninety-Three,
I totally agree that invoking humans here would have been useful! If the post hadn’t already been pushing 8000 words (and I didn’t have work to do on my master’s thesis lol) I probably would have done so!
In terms of why I think crows are grayer than humans, I think it’s because the assortive mating in crows is probably significantly more stable (and probably genetically determined) than assortive mating in humans. It’s true that humans do assortive mating, but it does not tend to be stable over anything approaching the geological time that is (usually) required for speciation. The Casta system in South America is a good example -- 350 years of legally enforced, super racist assortive mating that lasted for many generations, but eventually collapsed and now South America is one big intermingled, intermarried population. Interracial marriage statistics in the US are another example—they were insanely low before the 1950s, but have risen substantially since then as cultural mores changed, which is over only like 80 years. Social divisions from only like 1,000 or 2,000 years ago seem absolutely absurd to us now. Spartans being forbidden to. marry helots, for example. Nobody in modern day Greece has such a distinction. Because they all ended up interbreeding, despite assortive mating preferences and laws etc.
that whole time, the hooded crows and the carrion crows have been assortive mating. They’ve probably been doing so for a very long time, tens of thousands of years. This indicates that either 1) it’s very genetic, and relatively stably so, or 2) that crow “culture” (which does exist, can be seen in mating structure differences around Europe, though it’s obviously not comparable to human culture in extent) is also extremely stable. My guess is that it’s genetic, but I suppose both are possible.
In both these ways, this assortive mating looks different to evolution (and thus speciation) than human assortive mating. Since it’s so stable with these crows, we can say with (relatively) high certainty that these two populations will speciate along these precise lines, and probably very soon. We cannot say such a thing about any two populations of human with any certainty, because human culture and migration and history is so contingent and unstable.
I still don’t think this is a reason to split the crows. I stand by them being different species. This is just why I empathize with people who say they should be different species. They’re probably about to become them.