Human Evolution
Seven million years from the last ancestor we shared with other apes to the species writing this sentence.
A detailed zoom into the origin of our own species: the fossils, tools, and behaviors that mark the path from an ape-like common ancestor to Homo sapiens. This timeline expands three events from the wider Big Bang to Now spine, walking upright, the first stone tools, and the appearance of our species, into their full story, drawn from the Smithsonian's Human Origins Program and other authoritative sources. Built for zooming.
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Events
- About 7 to 6 million years agoDebated
Peer-reviewed · 2 sourceswhy?
Best source: Earliest evidence of hominin bipedalism in Sahelanthropus tchadensis (peer-reviewed, via PubMed Central)
Cited as a "journal" source (no stronger domain match).The first steps toward walking upright
The Smithsonian's Human Origins Program traces the oldest evidence for walking on two legs back to two of the earliest known species in the human lineage. Sahelanthropus tchadensis, dated to about 7 to 6 million years ago, may have walked on two legs, based on features of its skull. Around 6 million years ago, Orrorin tugenensis left behind a thigh bone whose upper portion resembles that of other large apes, but whose angled neck closely resembles a modern human's, forming what the Smithsonian describes as a strong bridge with the hip capable of supporting the body's weight while walking upright. For a long stretch afterward, from at least 6 to 3 million years ago, early human ancestors combined apelike and humanlike ways of moving, still capable of climbing trees while increasingly walking upright on the ground.
Why it matters: These two species sit right at the point where the human lineage splits from the rest of the great apes, and the evidence for how they moved is fragmentary by necessity: a skull here, a single thigh bone there. Walking upright is one of the very first traits that made our branch of the family tree distinct, long before bigger brains or tools arrived.
How we know: The Smithsonian Human Origins Program dates Sahelanthropus to about 7 to 6 million years ago and describes the skull evidence for possible bipedalism; it separately describes the Orrorin tugenensis femur and the anatomical reasoning connecting its shape to upright walking. Because the fossil evidence for these earliest species is limited, the interpretation that either walked upright is treated by researchers as likely rather than certain, so this event is marked as debated.
Sahelanthropus tchadensis: About 7 to 6 million years ago; skull evidence suggests possible upright walking · Orrorin tugenensis: About 6 million years ago; thigh bone shape suggests upright walking · Transition period: 6 to 3 million years ago: apelike and humanlike movement combined · Status: Evidence is fragmentary; bipedalism in these species is inferred, not certain
SourcesRelated timelines- Big Bang to Now → · Zoom out: this moment on the 13.8-billion-year timeline
- About 4.4 million years agoDebated
Peer-reviewed · 3 sourceswhy?
Best source: Ardipithecus ramidus and the paleobiology of early hominids (Science, 2009, via PubMed)
Cited as a "journal" source (no stronger domain match).Ardi overturns the savanna story
Between 1992 and 1994, a team led by paleoanthropologist Tim White found the first Ardipithecus ramidus fossils in the Middle Awash region of Ethiopia, but it was not until 2009 that the team announced their most important find: a partial skeleton nicknamed Ardi, about 4.4 million years old and one of the most complete early human skeletons ever recovered. Ardi's feet had an opposable, grasping big toe alongside more rigid remaining toes, her pelvis was short and broad, and her wrists could bend backward in a way chimpanzees and gorillas, built for knuckle-walking, cannot. Together, the Smithsonian describes this as a mosaic: she could walk upright on the ground while still moving carefully on top of branches using all four limbs, a gait called palmigrady, rather than swinging or knuckle-walking like a chimp.
Why it matters: Ardi's fossils turned up alongside evidence that she lived in a wooded environment, not open grassland, directly contradicting the long-standing theory that bipedalism evolved as forests gave way to savanna. Her anatomy also suggested the last common ancestor of humans and chimpanzees was not itself chimpanzee-like, reshaping how scientists picture the starting point of the whole human lineage.
How we know: The Smithsonian's Ardipithecus ramidus species page and its dedicated page on the Ardi skeleton give the 1992 to 1994 discovery by Tim White's team, the 2009 announcement, the wooded habitat and its challenge to the savanna hypothesis, and the specific foot, pelvis, and wrist anatomy. The Smithsonian is explicit that Ardi's pelvis was reconstructed from crushed fossils and that some scientists consider it only suggestive, not conclusive, of bipedalism, so this event is marked debated rather than settled.
Age: About 4.4 million years old · Found: 1992 to 1994, Middle Awash, Ethiopia, led by Tim White; announced 2009 · Anatomy: Grasping big toe, short broad pelvis, backward-bending wrists (no knuckle-walking) · Challenged: The savanna theory of why bipedalism evolved
Sources- Smithsonian Institution. Ardipithecus ramidus (Smithsonian Human Origins Program) (2024) · reference
- Smithsonian Institution. ARA-VP-6/500, 'Ardi' (Smithsonian Human Origins Program) (2024) · reference
- White et al.. Ardipithecus ramidus and the paleobiology of early hominids (Science, 2009, via PubMed) (2009) · journal
- 24 November 1974Well documented
Reputable source · 3 sourceswhy?
Best source: AL 288-1, 'Lucy' (Smithsonian Human Origins Program)
The domain "humanorigins.si.edu" is on our Reputable source registry.Lucy: forty percent of a skeleton, all the proof of upright walking
On 24 November 1974, at the site of Hadar in Ethiopia, Donald Johanson and his student Tom Gray, working within an expedition that geologist Maurice Taieb helped organize, found a small fossil skeleton later shown to be just under 3.18 million years old. Over two weeks of excavation the team recovered several hundred bone fragments, 47 of which formed a single skeleton representing about 40 percent of one individual, an exceptional proportion for a fossil this old. That night, celebrating at camp while the Beatles' 'Lucy in the Sky with Diamonds' played repeatedly, someone gave the skeleton the name Lucy; its Ethiopian name, Dinkinesh, is Amharic for you are marvelous or you are beautiful, depending on the source. Lucy's thigh bone, pelvis, and vertebrae all show adaptations the Smithsonian and the Institute of Human Origins describe as clear evidence of habitual upright walking, including a pelvis remodeled to balance the trunk over one leg at a time and a spine curved the way a modern human's is.
Why it matters: Lucy became the most famous single fossil in the story of human evolution because she offered something rare: enough of one skeleton, all from one individual, to argue convincingly from the bones themselves that her species walked upright as a matter of course, not as an occasional or debated behavior.
How we know: The Institute of Human Origins at Arizona State University, Donald Johanson's own research institute, gives a detailed account of the discovery date, the naming, and the specific skeletal evidence for bipedalism. The Smithsonian's Human Origins Program independently corroborates the site, age, and bipedal anatomy on two separate pages, though it credits Maurice Taieb alongside Johanson rather than naming Tom Gray, a minor, honestly-noted discrepancy in how different institutions credit the find.
Found: 24 November 1974, Hadar, Ethiopia · Completeness: About 40% of one skeleton (47 fragments) · Age: About 3.2 million years (precisely, just under 3.18 million) · Named for: The Beatles' 'Lucy in the Sky with Diamonds,' played at camp that night
Sources- Smithsonian Institution. AL 288-1, 'Lucy' (Smithsonian Human Origins Program) (2024) · reference
- Smithsonian Institution. Australopithecus afarensis (Smithsonian Human Origins Program) (2024) · reference
- Institute of Human Origins, Arizona State University. About the Fossil Lucy (Institute of Human Origins, Arizona State University) (2024) · reference
- About 2.6 million years agoWell documented
Peer-reviewed · 2 sourceswhy?
Best source: 2.6-million-year-old stone tools and associated bones from OGS-6 and OGS-7, Gona, Afar, Ethiopia (Journal of Human Evolution, 2003, via PubMed)
Cited as a "journal" source (no stronger domain match).The first stone tools: the Oldowan toolkit
By about 2.6 million years ago, early humans were deliberately shaping stone into tools. The Smithsonian's Human Origins Program describes this earliest toolkit, the Oldowan, as the most basic stone implements our ancestors made: hammerstones used to strike other rocks, the stone cores those strikes came from, and the sharp flakes knocked off in the process. Toolmaking then continues across the roughly 2.6 million years since, spanning thousands of excavated archaeological sites that have been studied and dated, an unbroken technological record from a chipped stone flake to the device this sentence is being read on.
Why it matters: Deliberate toolmaking is one of the clearest boundary markers between an animal that only uses what it finds and one that reshapes raw material on purpose. Every technology built by later humans, from bronze tools to spacecraft, descends from this first act of striking one rock against another with intent.
How we know: The Smithsonian Human Origins Program states that stone toolmaking spans the past 2.6 million years and describes the Oldowan toolkit by name: hammerstones, stone cores, and sharp flakes, recovered from thousands of archaeological sites.
When: About 2.6 million years ago · Toolkit name: Oldowan · What it included: Hammerstones, stone cores, sharp struck flakes · Evidence base: Thousands of excavated, studied, and dated archaeological sites
- About 1.89 million to 110,000 years agoWell documented
Peer-reviewed · 3 sourceswhy?
Best source: Early Homo erectus skeleton from west Lake Turkana, Kenya (Nature, 1985, via PubMed)
Cited as a "journal" source (no stronger domain match).Homo erectus builds a body for the long walk
Homo erectus lived from about 1.89 million years ago to as recently as 110,000 years ago, and the Smithsonian's Human Origins Program calls its earliest African fossils the oldest known early humans with modern human-like body proportions: relatively elongated legs and shorter arms compared to the torso, an adaptation for a life spent on the ground rather than in trees, built for walking and possibly running long distances. Individuals ranged from about 4 feet 9 inches to 6 feet 1 inch tall. A remarkably complete skeleton found in East Africa, an eight- to nine-year-old boy who lived about 1.6 million years ago and stood 1.6 metres tall, shows the same tall, lean build adapted to hot, dry environments. Homo erectus is generally considered the first early human species to expand beyond Africa, reaching Western Asia and as far as China and Indonesia, though whether it reached Europe remains uncertain.
Why it matters: Homo erectus is the first member of the human family tree that would look, from a distance, recognizably like a person, and it is the first to have actually gone somewhere: spreading out of Africa across two continents over the course of well over a million years. Everything about how later humans populated the planet begins with this species proving it could be done.
How we know: The Smithsonian's Homo erectus species page gives the date range, body proportions, height range, and geographic range including the Africa-to-Asia dispersal, and flags the Europe question as unresolved rather than settled. A second Smithsonian page on early human bodies adds the Turkana Boy skeleton's specific age, height, and build as a concrete individual example.
When: About 1.89 million to 110,000 years ago · Body plan: Elongated legs, shorter arms; built for long-distance walking · Height range: About 4 ft 9 in to 6 ft 1 in (145 to 185 cm) · Dispersal: First early human species to expand beyond Africa (Western and East Asia; Europe unconfirmed)
Sources- Brown, Harris, Leakey & Walker. Early Homo erectus skeleton from west Lake Turkana, Kenya (Nature, 1985, via PubMed) (1985) · journal
- Smithsonian Institution. Homo erectus (Smithsonian Human Origins Program) (2024) · reference
- Smithsonian Institution. Bodies (Smithsonian Human Origins Program) (2024) · reference
- By about 790,000 years ago (earlier use debated)Debated
Peer-reviewed · 4 sourceswhy?
Best source: Evidence of hominin control of fire at Gesher Benot Ya'aqov, Israel (Science, 2004, via PubMed)
Cited as a "journal" source (no stronger domain match).The control of fire
The Smithsonian describes the oldest definite control of fire at about 790,000 years ago, in the form of fire-scorched stone toolmaking debris and burned seeds and wood marking early hearths at Gesher Benot Ya'aqov in Israel, a site excavated by a team led by Naama Goren-Inbar and reported in 2004. The Smithsonian's own pages are careful to distinguish this from older, less certain claims: it notes that some researchers think cooking may reach back more than 1.5 million years, within the long span of Homo erectus, but frames that earlier date as a minority view rather than settled fact, and lists how well Homo erectus actually mastered fire as one of the field's genuinely open questions.
Why it matters: Fire changed what humans could eat, where they could live, and how they spent their evenings once darkness no longer meant simply going to sleep, but pinning down when that change began is difficult precisely because the physical evidence, ash and burned bone, degrades and can be produced naturally as well as deliberately. This event is a case study in the difference between a claim a museum will state outright and one it will only attribute to some researchers.
How we know: The Smithsonian's pages on Homo heidelbergensis and on hearths and shelters both state 790,000 years ago as the oldest definite evidence, and a dedicated page on fire-altered stone tools names the Gesher Benot Ya'aqov site, its 2004 discovery, and the team led by Naama Goren-Inbar. The Smithsonian's own hedging language, oldest definite, some researchers think, still unanswered questions, is preserved here deliberately rather than smoothed into a single confident date.
Most confidently dated evidence: About 790,000 years ago · Site: Gesher Benot Ya'aqov, Israel (excavated 2004, led by Naama Goren-Inbar) · Evidence: Fire-scorched stone tool debris; burned seeds and wood at hearth sites · Contested older claim: Some researchers propose over 1.5 million years, within the Homo erectus era
Sources- Smithsonian Institution. Hearths and shelters (Smithsonian Human Origins Program) (2024) · reference
- Goren-Inbar et al.. Evidence of hominin control of fire at Gesher Benot Ya'aqov, Israel (Science, 2004, via PubMed) (2004) · journal
- Smithsonian Institution. Homo heidelbergensis (Smithsonian Human Origins Program) (2024) · reference
- Smithsonian Institution. Fire-altered stone tools (Smithsonian Human Origins Program) (2024) · reference
- About 400,000 to 40,000 years agoWell documented
Peer-reviewed · 3 sourceswhy?
Best source: A Draft Sequence of the Neandertal Genome (Science, 2010, via PubMed Central)
Cited as a "journal" source (no stronger domain match).Neanderthals: our closest, and only interbred, relative
Neanderthals lived across Europe and southwestern to central Asia from about 400,000 to 40,000 years ago, and the Smithsonian's Human Origins Program calls them our closest extinct human relative. They had a large mid-face, angled cheekbones, and a large nose suited to warming and humidifying cold, dry air, on bodies shorter and stockier than a modern human's, and brains just as large as ours, often larger relative to their heavier build. They made sophisticated tools, controlled fire, built shelters, wore clothing, hunted large animals, and sometimes made symbolic objects; there is evidence they deliberately buried their dead, occasionally with grave offerings such as flowers. Neanderthals and Homo sapiens shared a common ancestor between about 700,000 and 300,000 years ago, and the two species inhabited the same parts of western Asia for 30,000 to 50,000 years, a period during which genetic evidence shows they interbred before Neanderthals disappeared from the fossil record entirely by about 40,000 years ago.
Why it matters: Neanderthals are not a footnote to human evolution; they are family. The Smithsonian's own genetic research finds that non-African modern humans carry up to 1 to 4 percent Neanderthal DNA today, and humans living as recently as 40,000 years ago carried even more, up to 6 to 9 percent, meaning a piece of this other species survived by becoming part of us.
How we know: The Smithsonian's Homo neanderthalensis species page gives the date range, location, physical and behavioral traits, burial evidence, the common-ancestor estimate, and the 30,000 to 50,000 year overlap with Homo sapiens in western Asia. A companion Smithsonian page on ancient DNA gives the specific interbreeding percentages, citing the peer-reviewed research (Fu et al., 2015) behind them.
When: About 400,000 to 40,000 years ago · Where: Europe and southwestern to central Asia · Overlap with Homo sapiens: 30,000 to 50,000 years, in western Asia · Neanderthal DNA today: Up to 1 to 4% in non-African modern humans
Sources- Smithsonian Institution. Homo neanderthalensis (Smithsonian Human Origins Program) (2024) · reference
- Green et al.. A Draft Sequence of the Neandertal Genome (Science, 2010, via PubMed Central) (2010) · journal
- Smithsonian Institution. Ancient DNA and Neanderthals (Smithsonian Human Origins Program) (2024) · reference
- About 300,000 years ago (discovery published 8 June 2017)Well documented
Peer-reviewed · 3 sourceswhy?
Best source: New fossils from Jebel Irhoud, Morocco and the pan-African origin of Homo sapiens (Nature, 2017, via PubMed)
Cited as a "journal" source (no stronger domain match).Jebel Irhoud pushes Homo sapiens back 100,000 years
Homo sapiens evolved in Africa during a period of dramatic climate change about 300,000 years ago, a date fixed by fossils from Jebel Irhoud cave in Morocco that are now considered the oldest known members of our species. Published in the journal Nature on 8 June 2017 by Jean-Jacques Hublin and colleagues, the find pushed back the origin of Homo sapiens by at least 100,000 years from what had previously been accepted. The fossils show large teeth and a long braincase similar to earlier species like Neanderthals, but a face, forehead, and jawbone much closer to a modern human's. The Smithsonian notes the finds suggest our species evolved across a wide area of Africa, with early populations interacting and evolving for hundreds of thousands of years before any dispersal beyond the continent. Anatomically, later Homo sapiens are marked by a lighter skeleton, a large brain averaging about 1,300 cubic centimetres, a thin-walled, high, rounded skull, and a flatter, more vertical face with smaller teeth and jaws than earlier humans.
Why it matters: This single discovery moved the starting line for our own species back by a hundred thousand years and changed the picture from one birthplace to a whole continent's worth of early populations. Every event on every human history timeline the site holds happens after this line, most of it in only the last sliver of it.
How we know: The Smithsonian's dedicated article on the Jebel Irhoud discovery gives the 300,000-year date, the site, the Nature publication date and lead author, the mix of ancient and modern skeletal features in the fossils, and the wider-Africa interpretation. The Smithsonian's Homo sapiens species page adds the anatomical description of the species and its climate-change context.
Date pushed back to: About 300,000 years ago · Site: Jebel Irhoud cave, Morocco · Published: 8 June 2017, journal Nature, Jean-Jacques Hublin and colleagues · Anatomy: Ancient braincase and teeth, but a modern-looking face and jaw
Sources- Smithsonian Institution. Homo sapiens (Smithsonian Human Origins Program) (2024) · reference
- Smithsonian Institution. Our species arose at least 300,000 years ago (Smithsonian Human Origins Program, on the Jebel Irhoud discovery) (2017) · reference
- Hublin et al.. New fossils from Jebel Irhoud, Morocco and the pan-African origin of Homo sapiens (Nature, 2017, via PubMed) (2017) · journal
Related timelines- Big Bang to Now → · Zoom out: this moment on the 13.8-billion-year timeline
- About 77,000 to 75,000 years agoWell documented
Peer-reviewed · 2 sourceswhy?
Best source: Emergence of modern human behavior: Middle Stone Age engravings from South Africa (Science, 2002, via PubMed)
Cited as a "journal" source (no stronger domain match).The Blombos ochre: the first symbol
In 1991, at Blombos Cave in South Africa, archaeologist Christopher Henshilwood found a piece of ochre, about 77,000 to 75,000 years old, bearing deliberately incised, geometrically organized cross-hatched markings. The Smithsonian's Human Origins Program describes the pattern as clearly organized rather than random, which suggests to researchers that the markings represent stored information rather than decoration made without a plan.
Why it matters: A tool can be explained by its use, but a deliberate, repeated, organized pattern with no practical function is something else: evidence of a mind capable of abstraction, of making a mark stand for something beyond itself. This is among the earliest physical evidence of that capacity anywhere in the human story.
How we know: The Smithsonian's dedicated page on the Blombos ochre plaque gives the site, its 1991 discovery by Christopher Henshilwood, its age of about 75,000 to 77,000 years, and the reasoning behind reading its markings as organized information rather than incidental marks.
Site: Blombos Cave, South Africa · Age: About 77,000 to 75,000 years old · Found by: Christopher Henshilwood, 1991 · Significance: Organized, non-random markings, read as stored symbolic information
- At least 50,200 years agoWell documented
Peer-reviewedwhy?
Best source: Narrative cave art in Indonesia by 51,200 years ago (Nature, 2024, hosted on PubMed Central/NIH)
Cited as a "journal" source (no stronger domain match).A hunting scene painted at least 50,000 years ago
In a cave called Leang Bulu' Sipong 4 on the island of Sulawesi, Indonesia, researchers found a large painted panel depicting a narrative hunting scene: wild pigs and small buffalo-like animals called anoas pursued by human-like figures carrying spears and ropes, several of which show non-human features. A 2024 study published in Nature, using a more precise uranium-series imaging technique, dated the scene to a minimum of 50,200 years, revising an earlier 2019 estimate of 43,900 years upward by more than 4,000 years. The researchers interpret the hybrid figures as therianthropes, composite human-animal beings, rather than straightforward portraits of hunters.
Why it matters: This is among the oldest known examples of narrative art anywhere in the world, older than Europe's famous painted caves, and the 2024 redating shows how actively this field of research is still being revised: the same panel got four thousand years older within five years, using a better dating method on the same paint. The therianthrope figures also suggest the artists could imagine beings that do not exist, a capacity researchers connect to early symbolic and possibly religious thought.
How we know: The 2024 study, published in Nature and hosted on PubMed Central, gives the revised minimum age of 50,200 years for the Leang Bulu' Sipong 4 hunting scene, states the original 2019 estimate it supersedes, and describes the therianthropic figures and their interpretation. Because cave art dating in this region has been revised more than once as techniques improve, this event states the current best estimate rather than treating any single number as final.
Site: Leang Bulu' Sipong 4, Sulawesi, Indonesia · Current dating: At least 50,200 years old (2024 study) · Superseded estimate: 43,900 years (2019 study, same panel) · Depicted: A hunt: pigs and anoas pursued by human-animal hybrid (therianthrope) figures
- At least 21,000 to 23,000 years agoDebated
Reputable source · 3 sourceswhy?
Best source: Oldest known human footprints in North America discovered at White Sands (U.S. National Park Service, September 2021)
The domain "nps.gov" is on our Reputable source registry.Footprints at White Sands push back the peopling of the Americas
At White Sands National Park in New Mexico, researchers announced in September 2021 that fossilized human footprints in the Tularosa Basin dated to at least 23,000 years old, thousands of years earlier than the roughly 13,500 to 16,000 year arrival previously accepted by most archaeologists. The National Park Service reports the calibrated radiocarbon dates as 22,860 and 21,130 years, derived from seed layers above and below the footprint layer. The finding meant humans were present in North America before the height of the last ice age closed the migration routes from Asia, extending the known period during which people coexisted with Ice Age megafauna. The U.S. Geological Survey states plainly that the original announcement sparked dissenting commentary throughout the scientific community, but a 2023 follow-up study using two additional, independent dating methods reproduced the same 21,000 to 23,000 year range, which the USGS says makes it highly unlikely all three lines of evidence are wrong.
Why it matters: How and when people first reached the Americas is one of the most actively contested questions in archaeology, and this is presented here as a genuine, ongoing scientific debate rather than a settled fact. The White Sands evidence is currently the strongest challenge to the old consensus, but it arrived through public disagreement and repeated testing, exactly how a real scientific claim is supposed to be handled.
How we know: The National Park Service's own account of the footprints and its original 2021 news release give the dates, the comparison to the old consensus, and the ice age migration implications. The U.S. Geological Survey's 2023 release documents both the scientific pushback the original dating received and the independent re-dating that reinforced it, including an on-the-record quote from the study's co-lead author about the initial skepticism.
Site: White Sands National Park, New Mexico · New dating: 21,000 to 23,000 years ago · Previous consensus: About 13,500 to 16,000 years ago · Status: Contested since 2021; independently reconfirmed by a second study in 2023
Sources- U.S. National Park Service. Oldest known human footprints in North America discovered at White Sands (U.S. National Park Service, September 2021) (2021) · reference
- U.S. Geological Survey. Study confirms age of oldest fossil human footprints in North America (U.S. Geological Survey, 2023) (2023) · reference
- U.S. National Park Service. Fossilized footprints, White Sands National Park (U.S. National Park Service) (2023) · reference