Why can't we domesticate all the animals in the world?

Why can't we domesticate all the animals in the world?

Humanity, from the very beginning of its, let’s be honest not particularly long existence on this planet, got comfortable pretty quickly and decided: why not remake everything around us to suit ourselves? Including other animals. We looked at wildlife and went: “Alright, you cow, you’ll produce milk. You horse, you’ll carry my body and that huge pile of firewood. You cat, you’ll purr and, at the same time, get on my nerves by sprinting around the house at 3:00 a.m. And you pig well, you’ll just snort amusingly and one day become bacon.”

And it all seems to work. Entire species labor for us. But if you look closer, the picture isn’t so rosy. Out of the millions of creatures that run, swim, and crawl across the planet, only a few dozen have signed a full “contract” with humans. The rest either read the fine print and decided not to deal with two legged swindlers, or tried to eat the interviewer right there during the interview.

And that raises a logical question: why do we have cavalry on horses, but no elite units riding war moose? Why could ancient civilizations keep cheetahs on leashes but never turn them into dogs 2.0? And why is your cat a masterpiece of selective breeding, while a bear is still a walking safety hazard with claws? To answer that, we first need to separate two concepts that are often confused.

Taming

It is about a specific animal and a specific human. You take a wild animal and gradually convince it that you are not food. Sometimes this is done with food, sometimes with patience, sometimes with less humane methods. But in any case, it’s a temporary agreement, with a clause in small print at the bottom that reads: “At the first opportunity, this contract may be terminated along with your arm.” In science, this is called taming, the modification of an individual animal’s behavior without changing the species’ genetics.

Domestication

It is a much more serious and, frankly, slightly unsettling process. This is no longer negotiation with a particular animal, but an intervention in evolution. Humans begin selecting individuals with desired traits and breeding only them. Generation after generation. Slowly, stubbornly, and with little regard for genetic diversity. From a biological standpoint, it’s natural selection except the decisions are made by humans instead of nature. And at some point, we truly begin rewriting the species’ “code.” This is where what scientists call the domestication syndrome comes in. If you look closely at domestic animals, you’ll notice a strange similarity. They often have shorter snouts, ears that seem to have forgotten they’re supposed to stand upright, spotted coloration, and tails that take on a life of their own, curling into odd shapes. Behavior changes too: aggression decreases, while a kind of naive trust increases to levels where the animal starts to resemble a perpetual adolescent.

The work of evolutionary biologist Adam Wilkins and his colleagues explains this quite elegantly. It all comes down to neural crest cells a special group of cells in the embryo that contribute to multiple body systems. They influence pigmentation, skull shape, nervous system development, and even the adrenal glands that regulate stress. When humans select the calmest animals, they are effectively interfering with the development of these cells. As a result, stress hormone levels like cortisol drop, and physical traits begin to shift as well. So, if we simplify it, we selected for “doesn’t bite,” and got “floppy ears and a cute face” as a package deal.

The clearest demonstration that this works came from Dmitry Belyaev’s experiment. In the mid 20th century, he set out to test whether domestication could be accelerated. Instead of thousands of years, he aimed for just a few generations. The method was almost insultingly simple: take wild foxes and breed only those that were least inclined to bite the researcher’s face off. Within a few generations, the foxes began behaving like dogs wagging their tails, seeking contact, making new sounds. Then changes appeared that no one had specifically selected for: white patches, floppy ears, curled tails. Behavior and appearance turned out to be far more deeply linked than previously thought.

Now it becomes clearer why domestic animals struggle so much without humans. If you release a cow into the forest, it won’t “remember its ancestors” and run into the sunset to dramatic music. It will be confused. Studies show that domesticated animals have reduced brain volume compared to their wild ancestors, weaker avoidance responses, and a diminished ability to find food on their own. Simply put, a cow doesn’t have a “survive at all costs” mode. It has a “wait for the human with the bucket” mode.

But even if we now understand how domestication works, that doesn’t mean you can take any animal and just “repeat the trick.” Biologist Jared Diamond examined this question in detail and came to a rather harsh conclusion: most species simply aren’t suitable. And it’s not because humans didn’t try, they tried, a lot. The problem is that the animal must match humans across a whole set of parameters. It must be relatively undemanding in diet, because feeding a picky gourmet is a dubious pleasure. It must grow quickly, or you’ll be investing years of your life into a highly uncertain project. It must be able to reproduce in captivity which is already a problem for many species. It must be social, with a clear hierarchy, so humans can fit into that system. And, crucially, it must not turn into an uncontrollable projectile under stress.

This is where things fall apart. Take the zebra, for example. It looks like a perfect candidate basically a horse, just with a designer paint job. But that’s an illusion. Zebras evolved in conditions where hesitation meant getting eaten. As a result, they react faster, defend themselves more aggressively, and are harder to control. They lack the clear social structure of horses. To a zebra, a human is not a leader but a strange object either dangerous or annoying. Historical attempts to tame zebras did exist, but they often ended in injury. At some point, people simply decided the stripes weren’t worth a broken jaw.

Bears are another extreme. They are intelligent, strong, omnivorous, and, at first glance, quite trainable. But there’s one problem: they’re solitary. Their biology doesn’t include an inherent need to submit to anyone.

Wolves and later dogs already have a concept of a pack and a leader. A bear has only itself. When it sees a human, its brain doesn’t run a “submit” script. It opens a menu with two options: “eat” or “leave.” And even if you raise a bear cub, you’re not its owner you’re just a strange neighbor who sometimes brings food. And one day, it may decide that you’re also on the menu.

The story with moose is almost comical if it weren’t so illustrative. The idea of using them as cavalry was actually considered. On paper, it looked fantastic: massive, powerful animals with impressive antlers. In reality, however, the moose turned out to be a nervous gourmet with an extremely sensitive psyche. It is picky about food, handles stress poorly, and, when frightened, turns into an uncontrollable battering ram. At that point, it doesn’t care whether you’re sitting on its back or standing in its way.

Elephants present an even more interesting case, because they can be deceptive. Humans have used them for thousands of years. They are trainable, strong, and even seem loyal. But biologically, they are not domesticated. They are still wild animals just tamed. The reason is simple and brutal: economics. Elephant pregnancy lasts nearly two years, maturation takes decades, and their upkeep requires enormous resources. From a selection standpoint, this is an almost impossible project. It’s far easier to capture an adult elephant and break its behavior than to try to breed generations of compliant ones. So every working elephant is not the result of domestication, but of taming.

In the end, it becomes clear: domestication is not a matter of human desire, but of biological compatibility. A species must be social, allow hierarchy, reproduce quickly, and not be prone to sudden bursts of aggression. There aren’t many such animals. And that’s why the list of domestic species is so short.

So no, nature is not a Disney fairy tale where you can befriend any animal and ride off into the sunset together. In reality, most animals will either run away or try to kill you. And sometimes they’ll do both, just in a different order.

by @lev_me_vision