When we write history, it tends to be tidy and led by great men. In real time, it’s messy but still astonishing. Last weekend, Yevgeny Prigozhin, who leads a private army called the Wagner Group, attempted what many have called a coup against Russian President Vladimir Putin. Technically, it failed. He landed in the Russian city of Rostov-on-Don, pledged to march to Moscow, and then turned around. Nothing about this series of events suggests expert planning or high competence. Prigozhin is a former prisoner and a former hotdog salesman. Staff writer Tom Nichols puts him in a league with “gangsters” and “clowns.”

But sometimes gangsters and clowns are the ones who shake up the established order. Prigozhin’s march lasted barely 48 hours, yet it seems to have changed the conversation about Russia. Putin appears shaken and, as staff writer Anne Applebaum put it, “panicky.” His response to such a direct threat has been surprisingly tentative. The mutiny may have technically failed, but it left some revolutionary thoughts in people’s minds. Putin is not, in fact, invulnerable. Which means Russians might have a choice.

In this episode, Atlantic staff writers Anne Applebaum and Tom Nichols explain this week’s wild turn of events in Russia and the door those events opened.

“We’ve lived with Putin for 23 years. We’ve kind of internalized his narrative that he’s untouchable and he can stay forever, and that he reigned supreme,” Nichols says about this remarkable moment. “That’s gone. And so I think it’s a pretty natural thing to wonder: If he’s not that powerful and if he doesn’t have that kind of support, how long can he remain in power?”

Listen to the conversation here:

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The following is a transcript of the episode:

Hanna Rosin: I’m Hanna Rosin. This is Radio Atlantic. Over the weekend, something wild happened in Russia. A man named Yevgeny Prigozhin seemed to start a rebellion. His private army, the Wagner Group, fights alongside Russian troops in Ukraine. But this weekend they turned their guns against Russia itself. They took over a major southern city called Rostov-on-Don and then pledged to march on Moscow, making it hundreds of miles before turning around.

Was this a mutiny? Was it a failed coup? People are debating Prigozhin’s motives and whether he thought he had internal support. Zooming out, though, what it means is that one man—a guy who was in prison, then became a hotdog salesman, and then rose up to become a loyal protégé of President Vladimir Putin—turned on Putin, humiliated him, and somehow survived. We’ve been told that Prigozhin is now in Belarus. Anyway, the news is moving quickly and there’s been lots of speculation. Two people I trust to ground us are Atlantic staff writers Anne Applebaum and Tom Nichols.

So Tom, the past week’s events in Russia have been called a coup and a mutiny; however, you refer to it as a falling-0out among gangsters. What did you mean by that?

Tom Nichols: Well, the problem is that the Russian state is a conglomeration of power players who are much like the five families—you know, in the old Godfather movie—these are mobsters, and Putin is the gangster in chief. But he has capos under him. And there was some issue there about territory and control with Prigozhin and his forces, who were going to be pulled in under another one of Putin’s cronies, the minister of defense.

And, um, things got outta control.

Rosin: So how does Prigozhin fit into that picture? Sort of where is he in the gangster taxonomy?

Nichols: Well, he’s got his own crew. He’s a powerful captain. He’s got his own army. He has, you know, 25,000 well-armed, battle-hardened men who answer to him. And another capo was threatening to take that away from him, and he wasn’t going to stand for that.

Rosin: So you see it less as a geopolitical battle than just an internal fight for power between two people?

Nichols: People have multiple motivations for doing things. I think a lot of what Prigozhin tapped into is real. People are, both in the military and back home, fed up with the way that the guys in Moscow have run this war and taken immense casualties and pretty much gotten nowhere. I mean, that’s a real thing.

It’s a real problem, but it’s also in part a struggle for power among these players. So there are multiple things going on here and, and not all of them, I think, are clear to us over here right now.

Rosin: Right. So Anne, looking towards the real motives that Tom brought up, Prigozhin has for a long time been openly criticizing the war in Ukraine and the motives for the war in Ukraine. What types of things has he been saying, and why do you think they struck a chord?

Anne Applebaum: For the last several weeks and months, really, Prigozhin has been blaming the leaders of the army, the leaders of the military, for failing to provide leadership, failing to provide equipment. I mean, he’s focused in particular on the minister of defense, [Sergei] Shoigu and the army chief of the general staff.

And he talks about them using very insulting language. He talks about Shoigu, you know, living a luxury life. And [Valery] Gerasimov being a paranoid, crazy person who shouts at people. These are very personal anecdotal descriptions of them. Um, which may well ring a bell among people around them as something that’s true.

More recently, and right before his strange ride to Moscow, he came out with a much more substantive critique. In other words, he began talking about the causes of the war itself. He said, well, the war was—the only reason we’re fighting this war is because Shoigu wants to advance. He wants to be a marshal. You know, he wants a better rank.

And because lots of people in Moscow were making money off of the 2014 occupations of Ukraine territories in the east that they gained at that time, and they want more. They got greedy and wanted more.

In other words, it’s not a war for empire. It’s not about the glory of Russia. It’s not about NATO. It’s not about any of the things that Putin has said. It’s just about greedy people wanting more. The appeal of this narrative is that it’s very comfortable for Russians to hear that there’s a reason why they’re failing. You know that there are specific people to blame.

Rosin: And you mean failing in the war in Ukraine?

Applebaum: I mean failing in the war in Ukraine in that they were supposed to conquer the country in three days and that didn’t happen. There’s been massive casualties [and] losses of equipment. It may also have an echo among people who want someone to blame for general misery. The economy hasn’t been going well for a while. People can see corruption all around them. It’s not like it’s a big secret. And pinning it on specific people saying these guys are responsible for failure might be something that a lot of Russians want to hear.

Rosin: Yeah. I can see as you guys are talking how it can be both a gangster war and something that is sincere and taps into a true vein of discontent. Like, it can be both of those things at the same time. Now, this question is for either of you: We are getting news trickling out this week about the possibility that Prigozhin had some kind of support in the Russian military. If that’s true, and I know that’s a big if, what does that change about how we should understand the situation?

Applebaum: So I assumed he had some kind of support in the military, both because of the way he behaved in Rostov-on-Don, where he seemed chummy with the generals at the head of the Southern Military District and where his soldiers were tolerated and almost welcomed in the city. He couldn’t have done that and he couldn’t have kept going without somebody being on his side. And it seems like he expected more, or he thought there would be more support, so that doesn’t surprise me at all. I mean, the precise names of who it was and what their motives were, I don’t think we really know that yet, although there have been concrete names mentioned in the press. But he clearly expected something more to happen.

Nichols: Yeah, I agree with Anne. I don’t think you march on Rostov-on-Don and then turn north toward Moscow and think that you’re on your own. There may have been some specific people that he had spoken to, but I think there was also a larger expectation—because remember, Prigozhin’s a pretty arrogant guy, and there is a lot of discontent in the Russian military—that he was just expecting that there would be units that he would just pick up along the way or that around Moscow would get word of this and say: We’re on your side.

And I’ve been curious about Putin’s tentativeness, his procrastination and all this, and I wonder, given these reports, whether he had concerns himself about which units—if he ordered an attack or if he wanted to do something more demonstrative—which units would actually obey his orders or which units would actually stay with him or join the mutiny if they were forced to make a choice. But again, we can’t know that for sure. But it certainly makes a lot of sense that Prigozhin wasn’t going to do this without having spoken to somebody in Moscow and in Rostov-on-Don.

Rosin: Right. So the reason this continues to be a live issue is because it matters who supported him. It matters because it speaks to the degree of insecurity on Putin’s side, and it speaks to sort of how strong the discontent is.

Nichols: It matters because it says that the Russian government and the Russian high command have serious stresses and cracks that are now obvious that had been either smaller early on and hidden, or that had somehow been papered over. But the idea that somehow Putin is completely in charge and invulnerable to challenges—that’s gone.

Rosin: Yeah, and that’s important. Now, Anne, if Prigozhin, as you say, was aiming for something bigger and it didn’t quite work out or technically failed, as we talk about it we still have to grapple with what happened on the other side, which is that he arrived in a Russian city and the citizens kind of shrugged. What did that tell you?

Applebaum: So I thought that was quite significant. We’ve all read many times these somber analyses of so-called polling data from Russia saying that people support Putin. What this showed was that the citizens of Rostov-on-Don weren’t particularly bothered that a brutal warlord showed up in the city, said he wanted to change some things and get them done.

Maybe he was going to go and take Putin’s people down. Maybe he was going to go and take Putin himself down. And they applauded him and they were taking selfies with him. And they started chanting when the Wagner Group was pulling out of Rostov-on-Don on Saturday evening—they were chanting, “Wagner, Wagner” in the streets.

That shows that the support for Putin is pretty weak. It’s passive. He’s the guy there and we don’t see any alternatives, but the instant an alternative emerges, well, you know, that might be interesting. I mean, Prigozhin is not exactly an attractive figure, but maybe from their point of view, he’s more honest; he seems more effective.

And as I said in the beginning, he’s offering them an explanation that’s psychologically comfortable. Why is this war going so badly? Why haven’t we won? Why is everything so corrupt? Why is the army so dysfunctional? Why are so many people dying?

Okay, well he just gave us a reason. The reason is because there are these corrupt generals in charge and they’re doing a bad job. And that’s something that people would like to hear. They want an explanation for this strange war that doesn’t seem to be going anywhere and is only causing damage.

Rosin: Now, Tom, in the aftermath of all of this, Putin has given a statement talking about treason, not naming Prigozhin explicitly. And given what Anne just said, and what you just said about how strong a challenge this actually is, what is this hesitation about? I mean, this whole incident could have ended with Prigozhin dead, but instead he’s in Belarus, or we think he’s in Belarus. And he’s alive, or we think he’s alive.

Nichols: I think both of them are feeling about to figure out who their allies are and they’re both making appeals to society that are meant to isolate. In Putin’s case, he’s just isolating Prigozhin without naming him, saying: Hey, all you heavily armed crack commando mercenary guys, I understand that you were led astray. And it’s okay to come home.

So when he talks about traitors, I mean, this isn’t Stalinism. He’s not saying, Oh, that whole unit, they’re all dead. He’s trying to plant internal divisions there. As is Prigozhin, who has been really careful to say, Look, I’m not trying to overthrow the president. I’m not trying to overthrow the government. But these two guys at the top, Shoigu and Gerasimov, the minister of defense and the chief of the general staff, they gotta go. And if I have to march to Moscow to get them out, then that’s what I’m going to do.

So they’re both being very careful not to proliferate more enemies in society or among the other elites than they need to. Now, for Prigozhin, that makes sense. For Putin, that’s very revealing. I mean, he’s the president of the country and here he is, kind of tiptoeing around, trying not to aggravate thousands of armed men who were part of a mutiny. So while they’re both doing the same thing, I think it’s really revealing that one of them happens to be the president of the country.

Rosin: Yeah, and as much as I understand the iconography of Putin is important—who’s weak, who’s strong—as a unit of analysis. Strong man, shirtless on a horse, does not necessarily wanna lose out to a hotdog-salesman ex-prisoner.

Nichols: Right. He actually appeared in public the first two times—he looked awful; I mean, it looked like a bunker video—where he is standing in front of a desk and he’s kind of raging to the camera. He finally came out again with all of the pomp and all the trappings of his office, coming down the big staircase and the honor guard snapping to attention.

And addressing the troops, the officers, he said something really interesting. He said: You prevented a civil war. Which is not true. Nobody actually did that. It’s certainly not true that the army put down a civil war in the offing. Nothing like that happened, and to make that appeal is to try to pull the military closer to the president, to say: You’re my heroes. I know you saved the country and you will keep saving the country. Which to me was a really striking thing to do. Again, as you and everybody’s been pointing out, Prigozhin is still—at least we think—still alive and running around issuing statements.

Rosin: So what comes next? After the break, we speculate. But with restraint.

[BREAK]

Rosin: Now, because both of you have studied the situation so closely, my natural temptation is to lob a lot of future-prediction questions at you. Like, what does this mean for Ukraine and what does the weakened Putin mean for a global order? Is it just too hard to speculate?

Applebaum: I feel there are so many missing pieces of this story and so many oddities about it that don’t add up. I would need to know more before I would be confident about telling you that, you know, at 7 o’clock on September the first, X or Y will happen next. Almost everything we know about this story, I mean, it’s like the shadows on Plato’s Cave, you know? We’re seeing the reflections of activities. There are these Russian military bloggers who you have to follow in order to understand any of this. And of course, they’re telling the story from their point of view.

State television is telling it from Putin’s propaganda point of view. It’s not as if we have a reliable source of information who will lay it out for us and give us the facts. Even the story as we’re speaking. I mean, this may even change before this podcast comes out, but as we’re speaking, we’ve been told by several very unreliable people that Prigozhin is in Belarus,—by the Russian spokesman and by the Belarussian.

And, you know, those people have lied so many times that until I see a photograph of Prigozhin, I don’t believe it. He’s gotta have a photograph of him in Minsk and I need to know that it’s not Photoshopped. And then I’m sure it’s true. So that’s why I think it’s very hard to—you don’t wanna make too many sweeping conclusions yet.

I mean, we know what we saw on Saturday. And what we saw on Saturday was a mutiny, and it did demonstrate far more weakness in the state and unpreparedness than anybody was certain was there. We know that Putin was the first to start using the language of civil war. He did it on Saturday morning, and so that indicates that he at least thinks something very serious was happening.

Which is an indication, again, that there may be more to the story to come, but making clear predictions about what will happen, certainly to the war in Ukraine—I mean, I’m not sure yet that it has affected the war in Ukraine. Maybe it will affect Russian troop morale. Maybe it lets us know that there will be more trouble with the military command.

But it hasn’t had a specific effect on the ground yet that we can see. And until that happens, I’m just reluctant to make too many predictions.

Nichols: Yeah, I think when it comes to the war in Ukraine, too many people have had this idea that all the Russian forces are going to stop and say, No, wait. We’re not going to fight until we get this sorted out. Um, they’re still fighting. The situation at the front is the situation at the front, and that doesn’t really change because of this.

So what Ukraine has to do, and the support we need to give them—that doesn’t change … the reluctance to prognosticate. Well, you know, there were a lot of people who said the Soviet Union couldn’t fall. People that study Russia have figured out that you can get burned on these predictions, in part because when you’re predicting stuff, you tend to be predicting the behavior of institutions writ large because you know how they operate. This is all contingent on individuals, and trying to predict the behavior of these kind of Mafia-like characters is really difficult to do, because that could all change in a moment when they decide to shift alliances or one of them runs afoul of another of them.

So I’m with Anne here. I don’t want to get too detailed about what’s going to happen next week … This definitely wounded Putin and he is in a different situation than he was.

I don’t think there’s any going back to sort of pre-June in Russian politics right now.

Rosin: Yeah, I mean that’s important enough. As you were talking, Tom, I was thinking if you write the histories of a lot of mutinies and coups, they do start with an action by someone who seems like a gangster and seems to be behaving in a ridiculous way. Like, coups can start in ridiculous ways.

Applebaum: It is also true that coups and mutinies that don’t succeed can have an impact on politics too. And there’s some famous examples from Russian history: There’s a revolution that doesn’t succeed in 1905, but it had a profound impact on the state. It forced the czar, Nicholas, to pass a constitution and create a Duma—a Parliament.

It very much changed the way that he was perceived. And then in the run-up to the Russian Revolution in 1917, there were also a number of strikes and moments, you know, and other, different kinds of events that happened. And some of them were unsuccessful. The Bolsheviks had a march that was unsuccessful, but ultimately there was a revolution.

They did take power. And those earlier events, you know, looked retrospectively more important than they may have seemed at the time. And it’s too early to say whether that’s what this is. But it’s clearly the case though that a failed event can have political consequences even beyond those of the immediate moment.

Nichols: Right. The 1991 coup was a complete clown show, and it failed. The guy that was actually was supposed to step in as president and replace Gorbachev was, like, drunk all the time, and the whole thing was just a complete mess. But it had a profound impact on the final days of the Soviet Union and on the collapse of the Soviet empire and the emergence of the countries of the post-Soviet space. Most mutinies and coups don’t succeed, but as Anne pointed out, they can have an immense impact just because they happened at all.

Rosin: Now all I wanna do is ask you guys to speculate, because now it’s very interesting. Now I’m thinking: Okay, so which directions does it go? You know, Is there a future for Prigozhin? Is he making a play to replace Putin one day? Are there other Prigozhins out there? I mean, are any of those answerable questions?

Applebaum: I think you can talk about options. Again, you can look at the past. It seems to me, in the case of Putin, one possibility is: Now that there’s been a challenge that didn’t succeed but that revealed weakness, will there be more challenges? And so you might say, Well, that’s clearly now an option in a way that it wasn’t before last week.

You could also guess that Putin might now try another crackdown. What do leaders do who have been weakened? Leaders like him. Dictators. Well, one of the things they do is they lash out and they try and reestablish their preeminence or their dominance. And they do that by arresting people or purging people. I don’t know what that would be in the case of modern Russia. Cutting off the internet? Or shutting the borders? I mean, you can sort of imagine scenarios, because he will now need to make up for the fact that he’s seen to be weaker. And I’m not saying either one of those will happen, but those are things that, based on how these things have played out in other times in other places, you can guess at.

Rosin: Yeah. Anne, as you look at this, I’m trying to put myself in your head. You’re sort of looking at the dictator’s playbook, watching how he rewrites the story of what just happened in real time and trying to see what other dictators would do or have done in the past. Is that how you track these events?

Applebaum: Yes. And I’m also thinking of Russian history. In the history of the Soviet Communist Party, every time there was a failure or a disaster, they would try to re-up the ideology and sort of restart the project and crack down. It goes in waves, all the way from 1917 up to 1991. And you can imagine a similar pattern working itself out here, yes.

Rosin: Yeah.

Nichols: I feel like I’m going back to the toolbox of the old-school Sovietology that I learned back in the 1980s. And so, rather than prognosticate, I’ll just say the things I’m looking for. I’m literally now looking at videos of who’s sitting next to whom at these meetings. Who’s still in. Who might be out.

I’m looking for personnel changes. Does the minister of defense survive? Does the chief of the general staff get replaced? This now becomes kind of a game of trying to follow all of these people and their portfolios as some kind of indicator of what’s actually happening behind the scenes.

Rosin: Tom, what’s the larger through line you’re tracking? You’re tracking the chess pieces—who’s going here and who’s falling off the board—but what’s the bigger story?

Nichols: I think it’s going to be: Is Putin trying to shore up his power base or is there an alternative base forming against him? I think that’s the thing to watch. You know, we’ve lived with Putin for 23 years seeming to be [invincible], except for when he first arrived in power and when he had a serious challenge around 2011.

We’ve kind of internalized his narrative that he’s untouchable and he can stay forever. And that he reigns supreme. That’s gone. And so I think it’s a pretty natural thing to wonder: If he’s not that powerful and if he doesn’t have that kind of support, how long can he remain in power?

Because until now he has made sure that there were no alternatives to him. And I think what Prigozhin did was to say, well, there could be at least some alternative. Maybe not good ones. But you can in fact oppose this guy and criticize his team and get away with it.

Rosin: Yeah. Basically, Russians, you might have a choice. That’s as much as we can say.

Nichols: Not a great choice, but a choice somewhere.

Rosin: Yeah. Anne, this may be a strange way to put it, but is there a sense that this incident exposes how alone, or kind of lost in his own head, Putin is? He conceived of the war in isolation. The military was never necessarily enthusiastic. Now we have a vision of him not exactly sure who his allies are and who’s on his team, and I just got this vision of: dictator alone.

Applebaum: So we’ve had intimations of that for a couple of years now. In fact, Prigozhin himself has hinted that Putin doesn’t really know what’s going on [and] they’re lying to him. And many others have said that too. So we’ve already had this idea that he doesn’t really know what’s going on on the battlefield. And this incident did make it seem like he also didn’t really know what was going on at home.

I mean, for someone who’s now saying they had foreknowledge of this, he didn’t react like somebody who was confident of the outcome. The speech he gave on Saturday morning was panicky. It was about the civil war in 1917 and “our nation is at stake.”

He didn’t give off the impression of someone who was staying in charge. And so there very much is the impression that he somehow lives in this by himself, surrounded by security guards in some bunker. And that feels more and more like an accurate description of his life.

Rosin: Yeah. Well, I guess a lot more to come this week. This year. For a while. But thank you both for helping us understand what just happened.

Applebaum: Thanks.

Nichols: Thank you.

Rosin: This episode of Radio Atlantic was produced by Kevin Townsend. It was edited by Claudine Ebeid, the executive producer of audio at The Atlantic. Engineering is by Rob Smerciak. Fact-checking by Yvonne Kim. Thank you also to managing editor Andrea Valdez and executive editor Adrienne LaFrance. Our podcast team includes Jocelyn Frank, Becca Rashid, Ethan Brooks, A. C. Valdez, and Vann Newkirk. We’ll be back with new episodes every Thursday. I’m Hanna Rosin. Thanks for listening, and we’ll see you next week.

If an alien life form landed on Earth tomorrow and called up some of the planet’s foremost experts on lactation, it would have a heck of time figuring out what, exactly, humans and other mammals are feeding their kids.

The trouble is, no one can really describe what milk is—least of all the people who think most often about it. They can describe, mostly, who makes it: mammals (though arguably also some other animals that feed their young secretions from their throat or their skin). They can describe, mostly, where it comes from: mammary glands via, usually, nipples (though please note the existence of monotremes, which ooze milk into abdominal grooves). They can even describe, mostly, what milk does: nourish, protect, and exchange chemical signals with infants to support development and growth.

But few of these answers get at what milk, materially, compositionally, is actually like. Bridget Young, an infant-nutrition researcher at the University of Rochester, told me milk was an “ecological system”; Alan S. Ryan, a clinical-research consultant, called it a “nutritional instrument.” Bruce German, a food scientist at UC Davis, told me milk was “the result of the evolutionary selective pressure on a unique feeding strategy,” adding, by way of clarification, that it was “a biological process.” A few researchers defaulted to using milk to explain something else. “It’s the defining feature of mammals,” says Melanie Martin, an anthropologist at the University of Washington. None of these characterizations were bad. But had I been that alien, I would have no idea what these people were talking about.

[Read: We’ve never been good at feeding babies]

What these experts were trying to avoid was categorizing milk as a “food”—the way that most people on Earth might, especially in industrialized countries where dairy products command entire supermarket aisles. “Overwhelmingly, when we think about milk, when we talk about milk, we think of nutrition,” says Katie Hinde, an evolutionary biologist at Arizona State University. That’s not the wrong way to think about it. But it’s also not entirely right.

The milk that mammals make is undoubtedly full of the carbs, fat, protein, vitamins, and minerals newborn mammals need to survive. And, across species, much of it does resemble the creamy, tart-tangy, lactose-rich whitish liquid that billions of people regularly buy. But to consider only milk’s nutrient constituents—to imply that it has a single recipe—is to do it “a disservice,” German told me. Mammalian milk is a manifestation of hundreds of millions of years of evolutionary tinkering that have turned it into a diet, and a developmental stimulus, and a conduit for maternal-infant communication, and a passive vaccine. It builds organs, fine-tunes metabolism, and calibrates immunity; it paints some of an infant’s first portraits of its mother, and telegraphs chemical signals to the microbes that live inside the gut. Milk can sustain echidnas that hatch from eggs, and wildebeest that can gallop within hours of birth; it can support newborn honey possums that weigh just three milligrams at birth, and blue-whale calves clocking in at up to 20 tons. Among some primates, it influences infants’ playfulness, and may shape their sleep habits and bias them toward certain foods. Some of its ingredients are found nowhere else in nature; others are indigestible, still others are alive.

Milk is also dynamic in a way that no other fluid is. It remodels in the hours, days, weeks, and months after birth; it changes from the beginning of a single stint of feeding to the end. In humans, scientists have identified “morning” milk that’s high in cortisol, and “night” milk that’s heavy in melatonin; certain primates have “boy milk and girl milk,” German told me, which support subtly different developmental needs. Tammar wallabies, which can nurse two joeys of different ages at once, even produce milks tailored to each offspring’s developmental stage; Kevin Nicholas, a biologist at Monash University, has found that when the joeys swap teats, the younger sibling’s growth accelerates. And when mothers and their offspring change, milk changes in lockstep. It reflects the mother’s stress level and physical health, taking on new flavors as her diet shifts; its fat content fluctuates, depending on how far apart bouts of nursing are spaced. Scientists are just beginning to understand how made-to-order milk might be: Some evidence suggests that maternal tissues may register, via the breast, when infants catch infections—and modify milk in real time to furnish babies with the exact immune cells or molecules they need.

“It’s a triad: mother, milk, and infant,” says Moran Yassour, a computational biologist at Hebrew University of Jerusalem. “Each one of them is playing a role, and the milk is active.” That dynamism makes milk both a miracle, and an enduring mystery—as unique and unreplicable as any individual parent or child, and just as difficult to define.

In its earliest forms, milk probably didn’t have much nutritional value at all. Scientists think the substance’s origins date back about 300 million years, before the rise of mammals, in a lineage of creatures that hatched their young from very delicate eggs. The structures that would later develop into mammary glands started out similar to the ones we use to sweat; the substance that would become proper milk pooled on the surface of skin and was slathered onto shells. The earliest milks probably had few calories and almost none of its hallmark lactose. But they were deeply hydrating, and teeming with immunity.

As our ancestors jettisoned egg laying for live birth, they began to extrude milk not just as a defensive shield for their offspring, but as a source of calories, vitamins, and minerals. The more that milk offered to infants, the more that it demanded of those that produced it: Mothers “dissolve themselves to make it,” German told me, liquefying their own fat stores to keep their babies fed, “which is impressive and scary at the same time.” In its many modern manifestations, milk is, in every mammal that produces it, a one-stop shop for newborn needs—“the only real time in life where we have hydration, nutrients, and bioactive factors that are all a single source,” says Liz Johnson, an infant-nutrition researcher at Cornell.

Each time mammals have splintered into new lineages, taking on new traits, so too has their milk. While most primates and other species that can afford to spend months doting on their young produce dilute, sugary milks that can be given on demand, other mammals have evolved milk that encourages more independence and is calorific enough to nourish in short, ultra-efficient bursts. Hooded seals, which have to wean their pups within four days of birth, churn out goopy milk that’s nearly sugar-free, but clocks in at about 60 percent fat—helping their offspring nearly double in weight by the time they swim away. Marsupial milk, meanwhile, is ultra-sweet, with double or triple the sugar content of what cows produce, and cottontail rabbits pump out a particularly protein-rich brew. (One thing milk can’t do? Be high in both sugar and fat, says Mike Power, a biological anthropologist at the Smithsonian Conservation Biology Institute, where he maintains a large repository of mammalian milk: “Nature has never been able to produce ice cream.”) Each species’ milk even has its own microbiome—a community of helpful bacteria that goes on to seed the newborn infant’s gut. Mammal milks are now so specialized to their species that they can’t substitute for one another, even between species that otherwise live similar lives.

Human milk—like other primate milk—is on the watery, sugary side. But its concentrations of immunity-promoting ingredients have no comparator. It bustles with defensive cells; it shuttles a stream of antibodies from mother to young, at levels that in some cases outstrip those of other great apes’ milk by a factor of at least 10. Its third-most-common solid ingredient is a group of carbohydrates known as human milk oligosaccharides, or HMOs, which aren’t digestible by our own cells but feed beneficial bacteria in the colon while keeping pathogens out. Roughly 200 types of oligosaccharides have been found in human milk—an inventory with more diversity, complexity, and nuance than that of any other mammalian species described to date, says Concepcion Remoroza, a chemist who’s cataloging the HMOs of different mammalian milks at the National Institute of Standards and Technology.

The sheer defensive firepower in our species’ milk is probably a glimpse into the challenges in our past, as humans crowded together to plant, fertilize, and harvest mass quantities of food, and invited domesticated creatures into our jam-packed homes. “We were basically concentrating our pathogens and our parasites,” Power told me, in ways that put infants at risk. Perhaps the millennia modified our milk in response, making those unsanitary conditions possible to survive.

Mammals would not exist without their milk. And yet, “we don’t actually know that much about milk,” down to the list of its core ingredients in our own species, says E. A. Quinn, an anthropologist at Washington University in St. Louis. Even for the breast-milk components that scientists can confidently identify, Quinn told me, “we don’t really have a good handle on what normal human values are.” Many studies examining the contents of breast milk have focused on Western countries, where the population skews wealthier, well nourished, and white. But so much varies from person to person, from moment to moment, that it’s tough to get a read on what’s universally good; likely, no such standard exists, at least not one that can apply across so many situations, demographics, and phases of lactation, much less to each infant’s of-the-moment needs.

Milk’s enduring enigmas don’t just pose an academic puzzle. They also present a frustrating target—simultaneously hazy and mobile—for infant formulas that billions of people rely on as a supplement or substitute. Originally conceived of and still regulated as a food, formula fulfills only part of milk’s tripartite raison d’etre. Thanks to the strict standards on carb, fat, protein, vitamin, and mineral content set by the FDA and other government agencies, modern formulas—most of which are based on skim cow’s milk—do “the nourish part really well,” helping babies meet all their growth milestones, Bridget Young, the University of Rochester infant nutrition researcher, told me. “The protect and communicate part is where we start to fall short.” Differences in health outcomes for breastfed and formula-fed infants, though they’ve shrunk, do still exist: Milk-raised babies have, on average, fewer digestive troubles and infections; later in life, they might be less likely to develop certain metabolic issues.

[Read: What parents did before baby formula]

To close a few of those gaps, some formula companies have set their sights on some of milk’s more mysterious ingredients. For nearly a decade, Abbott, one of the largest manufacturers of formula in the United States, has been introducing a small number of HMOs into its products; elsewhere, scientists are tinkering with the healthful punch via live bacterial cultures, à la yogurt. A few are even trying a more animal-centric route. The company ByHeart uses whole cow’s milk as its base, instead of the more-standard skim. And Nicholas, the Monash University biologist, is taking inspiration from wallaby milk—complex, nutritious, and stimulating enough to grow organs of multiple species almost from scratch—which he thinks could guide the development of formulas for premature human infants not yet ready to subsist solely on mature milk.

All of these approaches, though, have their limits. Of the 200 or so HMOs known to be in human milk, companies have managed to painstakingly synthesize and include just a handful in their products; the rest are more complex, and even less well understood. Getting the full roster into formula will “never happen,” Sharon Donovan, a nutritional scientist at the University of Illinois at Urbana-Champaign, told me. Other protein- and fat-based components of milk, specially packaged by mammary glands, are, in theory, more straightforward to mix in. But those ingredients might not always behave as expected when worked onto a template of cow’s milk, which just “cannot be compared” to the intricacies of human milk, Remoroza told me. (In terms of carbs, fats, and protein, zebra milk is, technically, a better match for us.)

A company called Biomilq is trying a radical way to circumvent cows altogether: It’s in the early stages of growing donated human-mammary-gland cells in bioreactors, in hopes of producing a more recognizable analogue for breast milk, ready-made with our own species-specific mix of lactose, fats, and proteins, and maybe even a few HMOs, Leila Strickland, one of Biomilq’s co-founders, told me. But even Strickland is careful to say that her company’s product will never be breast milk. Too many of breast milk’s immunological, hormonal, and microbial components come from elsewhere in the mother’s body; they represent her experience in the world as an entire person, not a stand-alone gland. And like every other milk alternative, Biomilq’s product won’t be able to adjust itself in real time to suit a baby’s individual needs. If true milk represents a live discourse between mother and infant, the best Biomilq can manage will be a sophisticated, pretaped monologue.

[Read: A bold and controversial idea for making breast milk]

For all the ground that formula has gained, “no human recipe can replicate what has evolved” over hundreds of millions of years, Martin, of the University of Washington, told me. That may be especially true as long as formula continues to be officially regarded as a food—requiring it to be, above all else, safe, and every batch the same. Uniformity and relative sterility are part and parcel of mass production, yet almost antithetical to the variation and malleability of milk, Cornell’s Johnson told me. And in regulatory terms, foods aren’t designed to treat or cure, which can create headaches for companies that try to introduce microbes and molecules that carry even a twinge of additional health risk. Float the notion of a very biologically active addition like a growth factor or a metabolic hormone, and that can quickly “start to scare people a bit,” Donovan, of the University of Illinois at Urbana-Champaign, told me.

As companies have vied to make their formulas more milk-esque and complex, some experts have discussed treating them more like drugs, a designation reserved for products with proven health impact. But that classification, too, seems a poor fit. “We’re not developing a cure for infancy,” Strickland, of Biomilq, told me. Formula’s main calling is, for now, still to “promote optimal growth and development,” Ryan, the research consultant, told me. Formula may not even need to aspire to meet milk’s bar. For babies that are born full-term, who remain up-to-date on their vaccinations and have access to consistent medical care, who are rich in socioeconomic support, who are held and doted on and loved—infants whose caregivers offer them immunity, resources, and guidance in many other ways—the effect of swapping formula for milk “is teeny,” Katie Hinde, of Arizona State University, told me. Other differences noted in the past between formula- and breastfed infants have also potentially been exaggerated or misleading; so many demographic differences exist between people who are able to breastfeed their kids and those who formula-feed that tracing any single shred of a person’s adult medical history back to their experiences in infancy is tough.

The biggest hurdles in infant feeding nowadays, after all, are more about access than tech. Many people—some of them already at higher risk of poorer health outcomes later in life—end up halting breastfeeding earlier than they intend or want to, because it’s financially, socially, or institutionally unsustainable. Those disparities are especially apparent in places such as the U.S., where health care is privatized and paid parental leave and affordable lactation consultants are scarce, and where breastfeeding rates splinter unequally along the lines of race, education, and socioeconomic status. “Where milk matters the most, breastfeeding tends to be supported the least,” Hinde told me. If milk is a singular triumph of evolution, a catalyst for and a product of how all mammals came to be, it shouldn’t be relegated to a societal luxury.

“Rebound relationships” have a terrible reputation. A romance ignited shortly after another ends seems chaotic—like an opportunistic ricochet rather than an intentional search for compatibility. After a breakup, people are commonly told to take their time grieving before they start dating again. And people dating someone who’s fresh off a breakup are told to be wary—of being used as a distraction, or being treated carelessly by someone fumbling through their own heartache. But research doesn’t seem to support the idea that rebound relationships are inherently toxic or doomed to fail.

When someone fresh from a split starts dating, it’s true that they might not be totally over their ex. But new relationships can help people move on from old ones. In one study of participants recovering from breakups, those who’d found a new partner were more confident in their own desirability, more trusting of other people, and less likely to say that they still had feelings for their old partner. Another examined rebounders who’d been in their new relationships for a year and a half on average. The quicker those subjects had jumped into that rebound, the higher they rated on measures of well-being and self-esteem.

Amy Hackney, a psychology professor at Georgia Southern University, found something similar when she investigated what helped college students get over breakups. “The sooner they began dating someone new, the faster that they felt that they had recovered from that prior relationship,” she told me. Although that might conflict with conventional wisdom, she thinks it fits with basic social psychology: A partner provides validation, care, and companionship, and when they go away, there’s no reason someone else can’t take their place. Perhaps that sounds unromantic, but according to Hackney, it’s healthy to be reminded—promptly—“how many people we really can have fulfilling relationships with.”

[Read: Stop waiting for your soulmate]

Rebounding can be especially helpful for certain people. Men, for instance, are more likely than women to believe in the idea of a one-and-only soulmate, and they tend to remain more emotionally attached after a breakup to their ex; they also have less social support than women do, on average, to help them mend. Perhaps unsurprisingly, then, they’re more likely than women to enter into rebound relationships. People with an anxious attachment style, who long for validation and fear abandonment, also tend to struggle with letting go of exes; pivoting to someone new can help them detach from an old partner, researchers have found, which can lead to growth—developing new interests, connecting with others, gaining confidence and independence.

As valuable as rebounds can be for the brokenhearted, they can still be destructive for the other person—say, if the rebounder isn’t open about being preoccupied with an ex, or relies too heavily on their new partner for solace. But the experts I spoke with said they wouldn’t assume that one partner’s progress comes at the expense of the other’s feelings, or that a new relationship is less meaningful if it comes on the heels of an old one. Cassie Shimek, a communication professor at Northern Virginia Community College, told me that when she started studying rebound relationships, she expected to find bonds that were largely superficial—but she was startled by how many blossomed into long-term partnerships.

She thinks that rebounds are really a phase, rather than a category, of relationships; if in the beginning one partner is processing a breakup, that might not mean much about the couple’s future. Indeed, one study found no link between the time since a woman’s divorce and the success of her next marriage. The author of that study, Nicholas Wolfinger—now a sociology professor at the University of Utah—summed it up bluntly: “There is no rebound effect.”

[Read: The scariest part of a relationship]

That doesn’t mean that every rebound relationship will work out. But of course, any romance carries the risk of deteriorating; every partner brings some sort of emotional baggage, and every new experience is shaped by past ones. We don’t have the luxury of neatly resolving all of our old hang-ups before moving forward, arriving in our next relationship as a clean slate.

Why, then, are people so skeptical of rebounds? Wolfinger believes that when people advise pausing after a breakup, it’s a way of acknowledging how important relationships are, and how major it is when one dissolves. The mistake comes in thinking that healing happens in a vacuum. “What does ‘sitting with my pain’ mean?” Wolfinger asked me aloud. “It means I sit in a darkened room and think about my loss?” That doesn’t strike him as realistic. “Human life,” he told me, “is a series of going from one distraction to the next.”

Kathrine Bejanyan, a psychologist who has studied rebounds and now works as a relationship counselor, told me that clients frequently ask her whether they’d be wrong to start dating shortly after a breakup, or simply before they feel that they’re “ready.” In rare cases, she said, when people have “heavy traumas” that they need to address on their own, it’s not a bad idea to take a breather. But she tells most people to go right ahead; after all, she noted, “We’re never finished products.” Whatever her clients are working on in their sessions—say, setting boundaries, or being more vulnerable—can really only be practiced in the real world, in relationships with other people. Past entanglements, however recent, don’t make you less fit for a new love; they actually might make you more prepared, because you learn from them.

[Read: What does it mean to be “ready” for a relationship?]

When I asked experts how people can try to rebound thoughtfully, some said the key is probably just honesty—being upfront about your breakup and its ongoing relevance. Your new love interest should understand, Shimek told me: Relationships that are important to us are rarely fully forgotten. “To expect us to completely shut the door on past feelings for someone who we had a strong, committed relationship with … That doesn’t make sense,” she said.

She believes that the rebounds that succeed are likely to be the ones that involve reciprocal emotional support: The rebounder leans on their new partner, and the new partner can be vulnerable too. That’s something she’s picked up on in her research—and in her own life. At one point, the man she was seeing opened up about his previous relationship, and she realized that she herself was in a rebound. “I welcomed the conversation,” she told me. “I didn’t shut it down.”

Today, they’re happily married. And when she teaches classes, she tells her students that partners don’t need to be damage free and completely self-sufficient in order to find a happy relationship. They just need to complement each other.