Same Genome, Different Animal

Polyphenism, plains horse cultures, and environments we haven't met yet

Author

Ray Doraisamy
July 24, 2026

In 1519, horses returned to the Americas after thousands of years. By the 18th century, the Comanche had developed a horse culture akin to Mongolians. No one from the Dzungar Khanate, or Golden Horde offshoots active at the time brought this culture to the Comanche. Yet, here, on the American plains, were a people where the communal hunt doubled as military organization, with a sacred bundle of objects housing a tent-spirit (ongon, anyone) that had to be ritually fed, with the horse as a supernaturally central figure, where horse stealing was heroic, and a round tent was a model of the universe. Oh, and centaur-like archery with Parthian shots.

In worldbuilding for tabletop role-playing games as a teenager, I used to wonder about why you'd get 'half-elves' or 'half-orcs'. Were they like mules, or ligers? Or were they more like the various coyote-hybrids that breed freely & truly across a few species?

Attend to fish, and it is easy to find many examples of the very same species looking very different depending on their environment, just as we see with domesticated dogs. What's called polyphenism.

Polyphenism happens across other species.

Consider the Locust

Some species of grasshoppers behave and look extremely differently depending on how many of their kind are around them. A locust is usually bigger and less camouflaged when members of that species are surrounded by lots of other locusts.

solitarious and gregarious phase locusts differ in a variety of other traits, including morphology, food selection and nutritional physiology, reproductive physiology, metabolism, neurophysiology, endocrinology, molecular biology, immune responses, longevity and pheromone production. In the Migratory locust of Africa, Asia and Australia (Locusta migratoria), the phenotypic differences are so extreme that the two phases were originally classified by Linnaeus as separate species, a mistake that was not appreciated until 1921 when Russian biologist Boris Uvarov proved that the two phases are not even different genotypes. The genetic instructions for producing the two phases are packaged within a single genome, with expression of one or other suite of genes depending on cues associated with crowding. Different locust species vary in the number of phase traits that they express.

Locusts, Stephen J. Simpson & Gregory A. Sword

Why does the difference matter? Read the Torah, Bible, and Quran and you might remember a certain plague. Locusts are a threat to farms. When the swarms get big enough, they are propelled by looking for food and avoiding getting cannibalized, so much so that one swarm crossed the Atlantic Ocean in 1988. 

Consider the Long-toed Salamander

In Deschutes county, Oregon, long-toed salamanders are found to have bigger heads and teeth when fed a diet of others of their species, in comparison to worms or shrimp. At altitude, they tend to take a longer time to mature, before becoming terrestrial. 

The presence of a cannibal body type formed with different environmental exposures no doubt led to Peter Watt’s decision to come up with the vampires in his hard science-fiction novels. Though, without fun, we might suggest that a more plausible cannibal body would be none other than what our ancestors had pre-domestication, with bigger jaws & teeth.

Consider the Periwinkle

A Perwinkle is a type of water snail. Crabs, that kind that many species evolve toward, eat almost anything. Including snails. 

When those snails are exposed to crabs who might eat them, their offspring grow thicker shells and smaller openings, to better defend themselves against crabs. When the snails don't have that many crabs around, and are exposed to more waves, their offspring develop a more squat body with a bigger opening so they have more traction with their one foot, and are less likely to get displaced by a wave.

The Environment Changed. Did We?

We live in an environment unlike that of our ancestors. What does that change in us? One narrow slice that Robin Hanson points out is that our values seem to be mimicking small-scale societies more than the values of mega-societies in the last few centuries. 

Some years ago, I imagined one aspect of the cultural change like a tree. The roots branch out to get water and nutrients from the soil, but above the ground they form a trunk to get closer to sun, for sunlight. Where it takes in sunlight, it branches out again. This follows a much broader design pattern that evolution favors: maximize surface area to take resources in, minimize transport of the resources within the organism. So for the last thousand years, we were in a trunk period. Go further back, and the roots are branched in. Now, we get a feeling like we're preparing to branch out again. Toward what, only our descendants will know.

What we do know is that if you throw humans on a steppe with large herds of four legged animals, bows, and horses, you get Mongols and Comanches. Cimmerians, Scythians, Saka, Alans, Xiongnu, and so on.

A key difference, besides time & technology, lay in their herds. The Eurasians herded their cattle whatever the species, they were pastoralists. If Plains Indians had more time with the horse, perhaps they would have domesticated the bison. With herding comes a better awareness of how to coordinate animals, people, and the traits necessary to unite disparate nomad tribes. But they didn't domesticate the bison, and they couldn't defend the herds, so they were dissolved before the Maxim machine gun. 

The first offworld settlers will respond to an environment where five to fifty people are forced to function or die when any tiny detail about the machine they live in is missed, without a chain of command, and no way to call for help.

Do you know of any cultures that had a similar environment?


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