How Pigs Would Evolve If they Lived in a Desert Environment

Ajouté : 2026-05-30

[00:00:00]There is a pig standing in a feedlot pen outside Amarillo, Texas, and the temperature is 39° C, and she is miserable in a way she does not have language for. She weighs 118 kg.

[00:00:12]She is 14 months old, which means she was supposed to be slaughtered 4 months ago, and the only reason she wasn't is a paperwork backlog at a processing plant that no longer has any employees.

[00:00:23]She is a commercial hybrid, part Yorkshire, part Landrace, part Duroc, bred over a century into a machine that converts corn into muscle as fast as biologically possible. She has almost no hair. Her skin is pink and unpigmented, and already on the parts of her back the shade structure doesn't cover, beginning to burn. Pigs cannot sweat. This is not a metaphor or an exaggeration. The species genuinely has almost no functional sweat glands, which is why the pen has misters, and the misters stopped running yesterday.

[00:00:53]She doesn't realize that all humans across the planet disappeared yesterday afternoon. She can tell the misters have stopped. The feed auger that fills the trough three times a day is silent, and the other 40 pigs in the pen are noisy and restless. To her, the disappearance is a plumbing problem. It doesn't have a plumbing issue. It's the first time since domestication that any animal has been placed before the evolutionary challenge that the desert poses.

[00:01:18]And she was bred for a barn the desert does not know. The desert's first act is to sort the pen.

[00:01:24]On the third day without water, the pigs are really in trouble. This size pig requires about 15 L of water per day during moderate weather, and much more in this heat, and the trough has been empty since the auger broke down.

[00:01:37]Pigs that can work out how to push through the rusted gate get to a stock tank that's half full two pens up. The pigs that don't, don't. About half the pen remains in the pen case.

[00:01:47]Day four, the walking to the open feedlot animals are not the strongest or the smarter pigs.

[00:01:52]Because they were the pigs that happened to be standing near the gate, and happened to lean on it, and happen to be built leaner than the rest. Because the heaviest animals overheat sufficiently to make it out of the pig pen, and the most hefty animals were the ones the pen was intended to produce.

[00:02:09]On the day the humans had disappeared, there were about 700 million pigs on Earth.

[00:02:14]Feral pigs are already present in the wet parts of the world, and already do very well. They will be just fine. The die-off is almost complete in desert feedlots, in the American Southwest, in Australia, in northern Mexico. Nine pigs walks out of Amarillo lot. They are sunburnt, dehydrated, and have never found food on their own.

[00:02:32]They are unsupervised, too, for the first time in a century of breeding. It is at this point that the desert begins to kill them fast, and molds them slowly.

[00:02:41]The first summer the filter becomes most important. Four pigs are there in the place of the nine pigs. The pinkest ones, those that turn their skin into open sores when they are exposed to the sun, get infected and slowly die.

[00:02:53]One boar in the group has darker mottled skin on his shoulders, something a leftover from some Duroc ancestor that a breeder would have seen and passed over, so a recessive trait. It was nothing in a barn. In the open desert, it means that his shoulders don't blister. He lives, and the next spring he creates most of the next generation.

[00:03:12]It's not a minor matter out here about pigmentation. It's the difference between a sow and a pig. The survivors also get to learn the one most important thing that the desert teaches them, and it's not a sexy one. It is digging. Pigs do root and wallow. It's their instinct.

[00:03:27]It didn't go away after 100 years of barns. He who digs a pit in the shade under a mesquite and lies in it is 10° cooler than he is who stands in the sun.

[00:03:36]Not creating this on their own.

[00:03:38]These are the holy days of the year that they are recalling. Of course, the wallow was always a thermoregulation strategy, and that is what it was farmers thought of as being about, mud and filth.

[00:03:50]It's a desert that took away all other choices, and left the old instinct out there alone in the spotlight. There is no longer a feedlot in year 50 in the landscape, just a scattered group of rusted steel. And there are a few hundred pigs around these, maybe in the arroyos around, and they are not the type of animals that walked out of the pen. They are smaller. That's the first surprise, and the second surprise is that it's counterintuitive.

[00:04:14]The story of evolution is supposed to be one in which things grow larger.

[00:04:18]However, this body mass of 118 kg was a made-up product. It was an output, just like a number on a scale is an output, and the corn has all but vanished. A smaller animal will have more surface area to volume ratio, so will require less water, less food, and importantly shed what it has and generate heat at a quicker rate. In year 50, the weight of the desert pigs is 40 kg. They're more similar in size to the wild boar that bred them than to the animals two generations ago, and they've arrived in 50 years.

[00:04:48]If you don't want to take the pig for slaughter weight, then you want to take it for its ability to survive August, and the body reorganizes quickly. They have longer legs proportionate to their bodies. For a feedlot pig, there was never a time when he had to walk anywhere. His food came to him. The pigs that are more built use less of this foraging ground and arrive less depleted a night after the wallow and the water source because they have a longer leg.

[00:05:14]In the desert, the pork industry's long preached of short-legged, barrel-shaped beast is a design blemish that's being quietly removed, and they have gone nocturnal. The feedlot pig was active when feed is present. The 50th-year-old pig does nearly nothing from 10:00 in the morning till 5:00 in the evening. It hunkers down in its digging hole, breathes slowly, and it lives its life in the dark when the surface of the desert risk which is heat and the air sinks 15°. This is one change in behavior, and it is the workday change from day to night that keeps these animals alive more than any changes to their body. Firstly, evolution tries behavior. Behavior is easily available and rapid. The bones follow. At year 5,000, the bones have come.

[00:05:58]This desert pig is a true different beast, and the most noticeable difference you'll notice is the nose.

[00:06:04]The snout is already a best digging implement in the mammal kingdom. As a pig has one of these cartilaginous discs with a dedicated bone, the prees nasal bone, which few other mammals possess.

[00:06:14]Equipment was already in the desert and was being tested to their limits.

[00:06:19]Now, the snout is longer, harder, stronger, and the main portion of this animal's survival strategy. It's the sole way to find water and food in the desert, so they have to stick it out there. These pigs forage for tubers, forage for bulbs, forage for root, then store moisture meters down. They are searching in a dry riverbed for the moist sand. They make dens, real dens, deep, 2 and 3 m. They make dens in the banks of arroyos, communal dens reused from generation to generation, a stable cool humidity. And the surface above it changes by 60° between the day's hottest and coldest hours. The boar's modeled skin has completed the action started by that skin. It is dark, thick, and sparsely hairy everywhere with very coarse bristles, which appear weird for a hot climate, but are not for warmth.

[00:07:04]It is a sunshade.

[00:07:05]The thin layer of bristle, which protects the skin from contact with the sun, also prevents the transfer of the sun's heat to the body and acts as a barrier of slightly cooler air.

[00:07:15]Desert mammals do this all the time. The desert always gives the same answers.

[00:07:20]The pig is the latest animal they've been given, and the ears have increased in size. The ears of the pig in the feed lot were average. The desert pig of year 5,000 had large, thin, well-vascularized ears that it could push away from its head, and which would be reddened on a quiet hot night when warm blood was pumped through them to radiate heat into the air. It's the same as a jackrabbit's ears, the same as this elephant's. A pig can't sweat 5,000 years ago and it can't sweat now. That door is closed. So, evolution looked for another door and it found one on the side of the head, radiators. The line of descent has parted ways by the 500,000th year. The desert never was nor ever will be one thing.

[00:08:01]There's open hard pan flat and there's rocky upland and there's the thin green ribbon along the seasonal rivers. And the pigs have flowed into all of it and are three animals doing it. The larger form, the coarser, is found on the open flats. Its size is up to 90 kg. Its legs are long and its chest is deep. It is designed to travel. On the flats, food and water are far apart and the only way to survive is to cover vast distances between food and water efficiently. They form groups of 20, roam largely at night, and have shed nearly all of their fur, which would keep them cool out here where heat radiated from skin surfaces was more important than shading from hair. And dark bare skin would radiate heat more quickly than bristled skin would reflect it. A smaller, stouter, more rock-flipping and leveraging form lives on the rocky uplands alone or in pairs, built in the other direction on the snout, where the moisture-shutting cactus flesh was fully complemented by the scorpion and the lizard. It has taught it to eat the prickly pear pads as no other pig ever has, using a calloused mouth that the soft-faced feedlot pig would never have known.

[00:09:06]Along the seasonal rivers is the third form and the least of all, for the river has the least. Still plays in actual mud. It still has hair. A farmer from the past who is able to see only this one may for a fleeting moment recognize it. It would then turn its head and he would see the ears, the snout, and the long, wary legs, and he would know that the recognition was a ruse. 2 million years ago, after the mister shut down, there's a pig standing in the dark on a hard pan flat, once a feedlot outside a city named Amarillo. Her weight is 85 kg.

[00:09:37]She has bare dark skin and is designed to radiate heat into the night air. Her legs are long.

[00:09:42]She has flaring ears, pumping blood through them to keep them cool, and her ears are parted from her head. Her snout is a hard exact tool, and an hour ago she dug it into the desert floor and found a cache of tubers 2 m below, which contained water for her ancestors, whom they could not have found, and which they could not have lived an hour without.

[00:10:02]She's been standing still for a long time now. 30 animals, the young in the middle, are in the process of hollowing out the shaded ground beneath the scrub, and she is the final one to get on top of the day.

[00:10:13]For there's something in her that keeps her awake a few minutes longer than the rest.

[00:10:18]She has nothing to wait for. No incoming call is received, but she scans the lightning horizon anyway.

[00:10:24]And only once they're settled, does she lower herself into her own dug hollow in the cool earth.

[00:10:29]The way her kind has lowered itself into the cool earth for 2 million years. The way the one pig once lowered herself into a misted feedlot pen because the heat was a misery it had no language for. It's the same animal doing an instinctual thing. A pig getting low, getting still, and waiting out the sun because it was too hot. The suffering has ended, though.

[00:10:49]What once was a nuisance in a barn, that digging, rooting, wallowing could not see that instinct being bred out 100 years. All but that instinct, that part of her the desert wanted to keep. All of the humans she made are removed. The one thing they tried their utmost to eradicate is what keeps her alive. The sun comes up over the hard pan.

[00:11:08]It's cool down there with the 30 pigs underground breathing slow, and the desert holds them as it holds everything that finally learned to listen to it.