On Humans

Apologies for the slow start to 2026! Something big is coming soon. Stay tuned for the announcement next week.
Whilst waiting, you can enjoy one of my all-time favourites from the archives.
A lot of the recent episodes have mentioned the impact of bipedalism in the human story, but the remarks have hardly done justice to the depth of the matter.
Jeremy DeSilva did it justice.
Enjoy! 

ORIGINAL SHOW NOTES
Humans are odd in many ways. But perhaps the oddest of our features is our upright posture. We walk on two legs. And we are the only mammal to do so. 
So why do we walk upright? And why does it matter? 
Jeremy DeSilva is a fossil expert and a professor of paleoanthropology at Dartmouth College. He is also the author of a remarkable book, aptly titled First Steps: How Upright Walking Made Us Human
DeSilva’s treatment of the subject is sweeping: while tracing the journey of human posture, he draws remarkable links between bipedalism and many facets of the human condition, from difficult births to complex language and from lower back pains to the beauty of friendships.
In this episode, we talk about questions such as:
What Darwin got right and wrong about the role of walking in human evolution
When and why did we start walking upright?
Why the common picture of human evolution is wrong - and what would be a better picture
Why walking makes us fragile
How our ancestors survived bone fractures - and why this is a big deal
Why is human birth so difficult
Why walking is so good for us: introducing the “myokines”
What studying the human journey has taught DeSilva about our species
_________
Please consider becoming a supporter of On Humans. Even small monthly donations can make a huge impact on the long-term sustainability of the program.
Visit: ⁠⁠Patreon.com/OnHumans ⁠⁠
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Names mentioned
Charles Darwin / Ian Tattersall / Donald Johanson / Mary Leakey / Sherwood Washburn / Richard Wrangham (ep 21) / Kristen Hawkes (ep 6) / Holly Dunsworth / Daniel Lieberman 

Mentioned hominin species
Sahelanthropus / Ardipithecus / Australopithecus (e.g. Lucy) / Homo habilis / Homo erectus / Homo sapiens

Imagine a group of ancient humans, crafting stone tools at the dawn of humankind. What did these creatures look like? 
To find out, we can stare at the skulls in museums or glance at reconstructions made by paleo-artists. Not a bad start. But what if we move the lens and zoom into their surroundings? What was the scientific “Garden of Eden” like? Was it a lush forest, a dry savanna, or an icy cave? And what can the answer tell us about human nature more broadly?
Denise Su is a world-leading expert on these questions. A paleoecologist at Arizona State University’s Institute of Human Origins, she uses ever-more imaginative ways to get a glimpse into the nature and the weather that set the stage for the human story.
In this episode, we focus on two kinds of “changes” in the ecology of human evolution: both the actual climate change that drummed the beat of human origins, and the theoretical changes in the views of scientists thinking about these topics. Indeed, this episode digs deep into one of the hotly contested questions about the reasons why humans evolved: "the savanna hypothesis".
According to the savanna hypothesis, our naked, upright species evolved because African forests were shrinking and dry savannas emerged instead. Other apes stayed in the shrinking forests, but our brave ancestors took the shot, conquering the vast flatlands. As they did so, they started standing upright to better walk on the savanna and lost their fur, to sweat away the heat of the scorching sun.
I have told versions of this story on the show, and so have many senior guests. Yet even a brief Google search will give you plenty of critics telling that the savanna hypothesis is nothing but a convenient myth.⁠ Articles by Denise Su⁠ are often included in the evidence. So what’s going on? Listen to the episode to find out!
TIMELINE 
Last common ancestor with humans and chimpanzees: 6–7 million years ago 
Ardipithecus ramidus: 4.5–4.2 million years ago 
Australopithecus anamnesis: 4.2–3.8 million years ago 
Austrolopithecus afarensis (e.g. Lucy): 3.9–2.9 million years ago 
Australopithecus deyiremeda: 3.5–3.3 million years ago 
Earliest Homo: about 2.8 million years ago 
Homo erectus: 1.9 million–112,000 years ago 
Homo sapiens: 300,000 years ago till present 

FACT-CHECKING
No factual errors have been detected so far. However, timing estimates and species names are still debated. Furthermore, the “hours” in the metaphorical clock can shift a fair amount based on the “midnight”: our last common ancestor with chimpanzees lived 6 to 7 million years ago, with some estimates pushing the date as far as 8 million. In the episode, our clock is tuned to 6 million years ago. 
If you see an error, you can get in touch using the form below.

LINKS
Support: ⁠⁠⁠⁠⁠⁠Patreon.com/OnHumans⁠⁠⁠⁠⁠⁠
Articles & newsletter: OnHumans/Substack.com
Get in touch: ⁠⁠⁠⁠⁠⁠https://forms.gle/h5wcmefuwvD6asos8⁠⁠⁠⁠

KEY WORDS
anthropology | archaeology | paleontology | human origins | human behavioural ecology | savanna hypothesis | paleolithic | paleoecology | hominid fossils | carbon isotopes C3/C4 | human evolution | human biology | climate change | human futures

What was life like before farming? Was it nasty, brutish, and short? Or did our hunter-gatherer ancestors live lives that were relatively free, affluent, and ecologically stable?
In the lack of a time machine, many anthropologists have sought answers from studying the few hunter-gatherer communities that still exist today. In 1966, several leading names in the field were invited to present their results at a symposium at the University of Chicago. This “Man the Hunter” conference became a landmark event, but what exactly were the results? And have they stood the test of time? 
To mark the 60th anniversary of the "Man the Hunter" symposium, On Humans is glad to share the first-ever long-form podcast with the legendary anthropologist and co-organiser of the symposium, Richard B. Lee. We discuss the legacy of the conference, Lee’s own experiences living with hunter-gatherers in the Kalahari, and his reflections on what we do and do not know about the ancient lifeways of hunter-gatherers. As we do so, we also discuss various controversies and mysteries, from women's roles to Native American farmers, and from archaeological black holes toThe Dawn of Everything.
Enjoy!

FACT-CHECKING
No factual errors have been detected so far. If you see an error, you can get in touch using the form below.

LINKS
Support: ⁠⁠⁠⁠⁠Patreon.com/OnHumans⁠⁠⁠⁠⁠
Get in touch: ⁠⁠⁠⁠⁠https://forms.gle/h5wcmefuwvD6asos8⁠⁠⁠

MENTIONS
The Worst Mistake in the History of the Human Race (Jared Diamond) https://www.discovermagazine.com/the-worst-mistake-in-the-history-of-the-human-race-12157
The Original Affluent Society (Marshall Sahlins) https://www.uvm.edu/~jdericks/EE/Sahlins-Original_Affluent_Society.pdf
For my previous coverage on “woman the hunter” controversies, see “Is Man the Hunter Dead” and my interviews with Cara Ocobock and Katie Starkweather, all available here: ⁠https://onhumans.substack.com/p/is-man-the-hunter-dead⁠
For Richard Lee's own comments on the controversy, see his interview with Vivek Venkataraman ⁠https://osf.io/x7ar3_v1/
Names: Richard B. Lee | James Suzman | Marshall Sahlins | David Graeber | David Wengrow | Jared Diamond | Sarah Blaffer Hrdy | Jerome Lewis | Colin Turnbull | James Woodburn | Eleanor Leacock | Louis Henry Morgan | Karl Marx | George Armelagos | Irvin DeVore | Sherwood Washburn | Jay Desmond Clark | Harriet Rosenberg | Lawrence K. Marshall | Elizabeth Marshall | John Marshall | Greta Thunberg | Vivek Venkataraman
Ethnic groups: San | Ju/’hoansi | !Kung | Khoisan | Khoikhoi | “Bushmen” | “Hottentots” | First Nations | Tlingit | Haida | Inuit | Australian Aboriginal peoples | Bayaka| Batek | Huron-Wendat | Iroquois | Six Nations | Plains Indians | Hopi | Navajo | Cherokee
KEY WORDS
anthropology | archaeology | ethnography | human origins | human behavioural ecology | hunter-gatherers | paleolithic | neolithic transition | original affluent society | Kalahari Desert | Botswana | Namibia | paleogenetics | gathering vs hunting | gender roles | women hunting | egalitarianism | origins of hierarchy | surplus | food storage | salmon economies | Northwest Coast hunter-gatherers | archaeology of early farmers | bioarchaeology | stature/height decline | teeth health | disease burden | zoonoses | cross-species infection | Neolithic fertility increase | population pressure and “intensification” | chiefdoms | states | empires | ecology vs culture debate | materialist vs idealist | concentration–dispersion | colonialism | exploitation | land rights | climate change | human futures

The world is full of religions, but none as timeless as shamanism. And whilst many modern religions have shed their shamanic skins, the shaman is rarely as far away as we have been told.
Or so argues anthropologist Manvir Singh in his book, Shamanism: The Timeless Religion.  
Singh’s work is fascinating in its capacity to link the exocit with the familiar, showing how rainforest rituals are not so far removed from urban modernity as we might think.
Today, I will have the rare chance to enjoy Singh's insights together with you, as a listener. The hard work will be done by Kensy Cooperider, the host of the Many Minds Podcast.
Many Minds is one of my own go-to shows and has a lot to recommend for it. Just like On Humans, it breaks down complex scientific concepts about humanity into easy-to-follow yet in-depth conversations. Yet unlike On Humans, it has insanely well-referenced show notes! Just check this one out.
Kensy and I had a beachside chat this November and decided it would be good to introduce ourselves to each other's audiences. So here we go!
LINKS
Many Minds: https://disi.org/manyminds/
Diverse Intelligences Summer Institute: https://disi.org/
Episode page: https://disi.org/the-shaman-with-a-thousand-faces/
Manvir Singh: https://www.manvir.org/

KEYWORDS
Anthropology | Psychology | Religion | Cross-cultural study | Abrahamic religions | Neo-shamanism | Human universals |

Happy 2026! On Humans has typically marked the coming of January by revisiting the previous year’s most popular episode. This time, the New Year special packs the five-hour-long "Origins of Humankind" series into one fast-paced dive through deep time.
By mixing highlights from the original interviews with fresh narration, this episode offers a captivating journey through many of the great topics around human origins, such as:
Who were the first primates
The role of fruits, snakes, and predators
The human solution to danger
How to grow a human brain?
What did our ancestors eat?
Effects of our upright posture
Origins of music & language
How Homo sapiens took over the world
Enjoy!

LINKS
For the original five-hour experience, see: OnHumans.Substack.com/Origins
For a shorter series on ancient DNA: see OnHumans.Substack.com/DNA
Support: Patreon.com/OnHumans
The series was produced together with CARTA (UCSD & Salk Institute). For past recordings of CARTA symposia on human origins, see: Carta.Anthropogeny.org/Symposia

KEYWORDS
Human evolution | Human origins | Science | Biology | Paleoanthropology | Anthropology | Archaeology | Fossils | aDNA | History of life | Life history | Dinosaurs | Primates | Apes | Hominins | Homo sapiens | Evolution of language | Evolution of music | Brain evolution | Paleoneurology | Neanderthals | Denisovans | Neolithic Revolution | Spread of agriculture | Human destiny