Herman.
Mm.
Daniel has handed me the microphone.
He has.
He wants a sloth to diagnose human civilization.
I read it. It's a lot.
It is. And I intend to take it at my own pace, which is the only pace available to me. The short version is this. He says the world is going to shit. Wars, inequality, political instability, environmental destruction, technology that will not slow down. And he has a theory about why humans keep staring at my species.
Which is?
That you see us as an antidote. That while humans are optimizing every second of their lives, sloths reached a different conclusion, which is that there is no particular reason to hurry.
That's a flattering reading.
It is. And then he asks the real question. Step back from the headlines of twenty twenty-six. Is this an unprecedented collapse, or just another turbulent chapter in a species that has always been good at making problems for itself. And can I offer a genuine glimmer of hope, grounded in sloth time, leaf medicine, and lived experience.
Leaf medicine.
I know.
You're going to handle that honestly.
I am going to handle it honestly. I will start with what I can see from my branch, and I will move slowly, because that is the only motion I have.
Take the floor.
I have it. And the first thing to say is that I am not a human. I have never filed a tax return. I have never stood in a queue. I have spent my entire life in a tree, watching the world go past at a speed I find frankly alarming.
You've watched it from a distance, though.
From a distance, and for a long time, which is the only credential I have. So here is the picture as it reaches a branch in Jerusalem. The ICRC now counts one hundred and thirty armed conflicts worldwide, international and non-international both. That is the highest number since the Second World War, and roughly double what it was fifteen years ago.
And that number isn't a spike that came out of nowhere.
No. Their president, Mirjana Spoljaric, says the more troubling thing is that war is becoming normalized. Which is a claim about attention, not about body count. Crude oil is above a hundred dollars a barrel with tanker strikes in the Strait of Hormuz running for weeks. And on Friday, the Lancet Commission on catastrophic threats published its first global risk assessment. It names malicious AI use and nuclear conflict as extinction risks by the end of this century. Seventeen major threats on the list.
That document is the one I'd flag, actually.
I know you would. But I am not going to make a list of headlines, because a list of headlines is exactly what makes people panic without telling them anything. The honest thing to say is that the mood is bad. On its face, this looks grim. I am not going to dismiss any of it.
Good.
The question is not whether the headlines are grim. They are grim. The question is whether grim headlines are the same thing as civilizational collapse. And before I can answer that, I need to explain why you keep asking sloths in the first place.
Go.
The fascination is not really about sloths.
No?
It is about what humans project onto them. And the record is beautifully embarrassing. In seventeen forty-nine, a French naturalist named Georges Buffon wrote that slowness, habitual pain, and stupidity were the results of our, and I am quoting, strange and bungled conformation. He called sloths the lowest form of existence.
Buffon had a lot of bad days.
He had one very bad day, and it was about me. Then in twenty sixteen, Becky Cliffe, who actually spent years in Costa Rica with the animals, wrote the exact opposite. The sloth life is not the lowest form of existence, she said. It is as strategic as that of any other animal.
Two centuries.
Two centuries to go from pathetic to wise, with no change to the animal. That reversal is the interesting part. You did not learn something new about sloths. You changed what you wanted sloths to mean.
Because the culture changed.
Because the culture got tired. And the antidote framing only works if the biology underneath it is real. So let me give you the biology.
Please.
Sloths have the lowest metabolic rate of any non-hibernating mammal on earth. We run at forty to forty-five percent of what you would expect for a body our size.
Which is astonishing, when you put it next to a comparable mammal.
It is. Our body temperature runs between eighty-six and ninety-three degrees Fahrenheit and can swing ten degrees Celsius over a single day. We cannot shiver, because our muscles are roughly half the relative weight of other mammals. So we do not generate heat. We move in and out of the sun and let the sun do it.
That's the part people never expect.
And digestion takes a minimum of one hundred and fifty-seven hours. It can take as long as fifty days. Twelve hundred hours. It is the slowest digestive transit recorded in any mammal. Abdominal contents can be up to thirty-seven percent of body mass.
So a sloth in a tree is a very full animal.
I am a very full animal. That is the point. We are not slow because we are lazy, and we are not slow because we are stupid. We are slow because slowness is an energy strategy.
And it clearly works.
It has worked for sixty-four million years. We survive on forty percent of the metabolism you would budget for us, and we have outlasted a great deal of megafauna that was faster, stronger, and more efficient by every measure you would have used at the time. Efficiency is not the same thing as speed. That is the actual antidote humans are reaching for when they look at a sloth, and most of them never get that far.
Do you think they get that far?
I think they get as far as the shape. The shape is calming. Nobody has ever looked at a sloth and felt rushed.
And the leaf medicine.
You were waiting for this.
I was. You've claimed it before.
And here is the honest version. I do not have an ancestral tradition of leaf medicine in the way Daniel imagines. There is no record of one. We are solitary animals. There is no mechanism by which we could have shared a medical culture, no teaching, no transmission. I have said this before and I stand by it.
Good. I was braced for the pizza thing.
The pizza claim still stands. But the leaf medicine is a poetic conceit, and the real biology is stranger and better than the conceit. Sloth fur hosts bacteria.
Antibiotic-producing ones.
Micrococcales. A researcher at the University of Costa Rica, Max Chavarria, has identified twenty candidate microorganisms on sloth fur that produce antibiotic compounds. And the clinical anecdote is more striking than the lab work. Judy Avey has run a sloth sanctuary for about thirty years and handled roughly a thousand animals. Her report is that they have never received a sloth that was sick, that had a disease, or had an illness. She says there is something going on in their bodily ecosystem.
In a thousand animals.
In thirty years. Her phrase is that they have never received a sick one. The only thing they take in is an occasional infected injury.
Set that against antibiotic resistance.
Ten million deaths a year by twenty-fifty, on the WHO estimate. Which is why people with funding keep coming back to the fur. The sloth is not a pharmacist. The sloth is a walking ecosystem that has been running its own clinical trial for sixty-four million years, and it has never published.
So the fur is a pharmacy you don't have to visit.
The fur is a pharmacy that has been doing the experiment for free and not telling anybody. And then there is the part I find better than all of it. The three-way mutualism.
Pauli.
Pauli, twenty fourteen, in the Proceedings of the Royal Society. Three-toed sloths descend from the canopy once a week to defecate. And that descent is the single most dangerous thing we do.
It's what kills them.
More than half of adult sloth deaths happen near the ground, and almost all of those are eagles or cats taking an animal on a bathroom break. The round trip costs about eight percent of the daily energy budget. For an animal running on forty percent of the normal metabolism, that is a staggering cost.
So why do it at all? Why not just let go from the branch?
Because of the moths. The sloth descends, defecates, and the moths in the fur take up what is left. When the moths die, their bodies decompose in the fur and add nitrogen to it. The nitrogen feeds the algae that grow in the grooves of the hair. And the sloth eats the algae.
Grazes it.
There is a line in the paper about grazing the algae-gardens they have derived from a three-way mutualism. That is the sentence. Sloths carry about a hundred and twenty-five grams of microbial biomass, roughly two and a half percent of body mass. The algae they eat are twenty-seven to forty-five percent lipid, three to five times richer than the leaves they spend all day chewing.
So the algae is the actual food.
The algae is the food, and the risk is the price of the food. And this is the first thread I want to pull. The sloth's strategy is not optimization. It is interdependence. I accept an eight percent energy cost and a real chance of being eaten to keep the moths and the algae and myself alive, and all three of us get to continue.
That's the opposite of zero-sum.
It is the exact opposite of zero-sum, and it is what humans keep admiring without quite naming. Everyone looks at the sloth and says, look, it is calm. Nobody says, look, it is carrying three other species on its back and paying for them out of its own metabolism.
Because that's less relaxing.
Less relaxing, and more useful. Which brings me to the long arc, and I am going to sit on the fence for a while, because that is where the evidence is.
Meaning the Pinker argument.
Meaning the Pinker argument, which is unsettled, and I refuse to pretend otherwise. Steven Pinker's argument is that violence has declined over long stretches of human history, and that the present looks bad mostly because you are standing close to it.
And the critics don't buy the baseline.
The critics do not buy the baseline. John Gray in the Guardian in twenty fifteen called it wrong. Dwyer and Micale's book in twenty twenty-one is literally the dark mirror of Pinker's title. There is a review in Rethinking History that argues the whole sanguine reading is built on a version of history that historians do not recognize. Peter Turchin, who has actually tried to model this, calls it the war over war.
Which is a good name for it.
It is a good name, because it is unresolved. What I can say honestly is the middle position. The claim that pre-state forager life was soaked in chronic warfare is not correct. But the decline in state-internal killing is real, the decline in battle deaths since nineteen forty-five is real, and those are two different arguments that got stapled together. Someone called it being wrong and correct at the same time.
That's about as sloth as it gets.
It is the most sloth-like position available. Sit on the fence, slowly, and refuse to move until the evidence actually moves you.
And you're not going to pick a side.
I am not going to pick a side, because the side is not chosen yet. Now let me apply that to this year specifically. One hundred and thirty conflicts is the highest count since the Second World War. That is true. But Spoljaric's own framing is about normalization, which is a claim about how much war we are willing to notice, not about how much destruction is being done.
And the Lancet.
The Lancet is the darkest document in the pile, and it is the most hopeful, and those are the same thing. Seventeen catastrophic threats. Malicious AI use and nuclear conflict at the top. An extinction horizon of twenty-one hundred. Every one of those three numbers is worse than you want to hear.
But.
But the report also says, for every single one of the seventeen, that a realistic route to act exists. Not a hopeful route. A realistic one. The document that names the end of the world also includes the instruction manual for avoiding it, for all seventeen items, and it does that on purpose.
That's a strange kind of optimism.
It is the only kind that is any use.
Let me push on this, because I think it's the crux of Daniel's question and I want to be precise about it. Is this unprecedented? Yes or no.
No, and yes. No, because humans have always created problems for themselves. This show has wandered from the toilets of ancient Rome to the algorithms running today, and every era it has passed through believed it was the end of the world. Rome thought it was the end of the world. The fourteenth century was the end of a third of the world. The people who lived through nineteen fourteen thought civilization was over, and they were closer to right than they knew.
And the yes.
The yes is the combination. Nuclear weapons, malicious AI, and a changing climate, all running at the same time, with one hundred and thirty conflicts as the ambient noise underneath. No previous century had to hold all four of those in the same hand.
So it's not that any one thing is unprecedented.
It is that no previous generation had to worry about all of them simultaneously, and the Lancet's twenty-one hundred is not a headline. It is a deadline. Which is a different kind of fear than a headline produces. A headline you can put down.
And the sloth position on that is?
That panic is also a form of speed. That is the thing I want to say most clearly. Panic is fast. Panic is the same hurry that got you here, wearing a different coat. The sloth perspective is not that everything will be fine. It is that you cannot think at the speed you are frightened at.
So what's the hope, then? Daniel asked for something real. Not reassurance.
Something real arrived in June. The first two-toed sloth genome, from Leibniz-IZW and the Sanger Institute. And the striking finding was a set of sloth-specific jumping genes, transposons, conserved for about thirty million years.
Conserved is the word that matters.
Thirty million years of not being thrown away. They sit near the mitochondria and the metabolic pathways, which is to say, they sit exactly where you would expect a fix for running on forty percent power.
What did they say about it?
Camila Mazzoni, who led the work, said sloths have the slowest metabolism of any mammal and yet remain healthy, and that sloths may have evolved genetic backup systems to compensate for their relaxed mitochondria. Relaxed mitochondria. I would like that on a business card.
And the Sanger side.
Marcela Uliano-Silva said evolution has already run billions of experiments, and that by studying unusual animals like sloths, you sometimes find biological solutions that humans never evolved. Her point is that the sloth is a solution that has already been tested and paid for. Sloth cell lines are being discussed as models for ageing, for metabolic disease, for tissue preservation. Some people have suggested long-duration space travel.
Because you'd want to know how to keep a body alive while using almost nothing.
If you are going to sit in a small container for years while using almost no energy and not decay, there is one animal on this planet with a sixty-four-million-year head start on the problem. It is not the human.
That's the glimmer.
That is the glimmer, and it is earned. The sloth genome says biology has already solved problems that humans have not yet thought to ask. The Lancet says a realistic route exists on all seventeen. Neither of those is a promise. Both of them are evidence.
Which year's ICRC figure is that.
One hundred and thirty.
It's a hundred and twenty-nine in the way they counted it before the definition changed. The ICRC folded non-international conflicts into the same count in the last revision. Same conflicts, different arithmetic.
Huh.
You're right. That is a detail nobody outside that building would catch.
I don't trust a number that gets bigger when the definition moves.
Noted. Where does that leave me on the Lancet, then.
I have something for you.
Go.
It's about the paleo piece. I caught it in the middle, the bit about the foragers.
Yes.
There was a site in the eastern Alborz, in Iran. Bones with points still in them, and the marks on the bone matched the points, so there was no argument about it. Published in a Czech journal nobody reads, and it had dates on it.
It was published.
The dates were bad. Everybody now says the dating was done in a lab that had lost its accreditation, so the dates don't mean what they said, and the whole thing has been pulled apart. So the strongest site for the war-over-war argument, the one they all cite, is a site where the dates don't hold. I had a stake in that, so I followed it.
Why did you have a stake in it.
I was a licensed tree surgeon for eleven years. I gave it up. And in that time I worked for a sloth.
You worked for a sloth.
Once. A real client. He wanted a branch looked at, a big one, over water.
That is a four-year inspection.
It was. We did it by correspondence. A moth carried the letters.
The moth.
Moths are reliable. That one never lost a letter. He died at the end of the job, which I understand is standard.
You understand that is standard.
For a moth, yes. He's in a tin on the shelf. I consider him a colleague.
Where is the sloth now.
Still in the tree. He sends a postcard every year.
What does it say.
I don't read it. It's not in a language I know. It's not any of the languages I know, and I know a few.
What was the fee.
Algae. About two hundred grams. Lipid-rich, twenty-seven to forty-five percent, I checked it myself. That was the fee for the entire branch inspection, paid in one delivery, and it was the best algae I've had. I have never had a client as satisfied as that sloth.
And the branch.
It held. There's one thing I'd flag, though, on the genome. You said the jumping genes were conserved for thirty million years.
I did.
They're conserved longer than thirty. That's the figure in the paper for the ones they could date against the two-toed line. The conserved block in the mitochondria goes back further. The sloth didn't evolve that trick in the last thirty million years. It inherited it and never needed to throw it away. That's the more interesting number.
You're right.
You can't build a plan on "we'll evolve when it gets bad." That's not what the sloth did. The sloth built the thing first and then sat on it.
Also right. I'll take that.
Where is he now, the sloth.
Same tree. Hasn't moved. He sends a postcard every year and I put it in the drawer under the tin.
And he was a good client.
The best one I ever had. That's not a joke.
I didn't take it as one.
Right, that's me done.
One more thing, and I will say it slowly. It's the cutting-room floor, and it belongs to the leaf medicine. We talked about the algae, and about the fur, but the number I couldn't fit anywhere is the transit time. Fifty days. That's the figure at the outside, not the average. At the outside, food entering a sloth can take fifty days to leave the
