Seven Million Years, One Survivor

The oldest proposed member of the human lineage, Sahelanthropus tchadensis from Chad, lived between 7 and 6 million years ago, according to the Smithsonian Institution’s Human Origins Program. Set those 7 million years on a calendar that starts on January 1 and the first stone tools appear on July 12, the first hominins outside Africa on September 26, and Homo sapiens on December 15. The painted and stenciled rock art and the footprints in the Americas discussed below fall in the last four days of December (Exhibit 1).

For most of that time several kinds of human lived at once. Exhibit 2 charts 22 named species and the Denisovans; around 1.8 million years ago five of them overlapped. Homo sapiens is the only one of the 23 with no end date.

The family tree

The record falls into three stretches. From 7 to 4.4 million years ago it holds a few fragmentary candidates: Sahelanthropus, Orrorin and Ardipithecus. From 4.2 to about 2 million years ago the australopiths dominate it; Australopithecus afarensis, the species of the 1974 Lucy skeleton, is dated by the Smithsonian to 3.85–2.95 million years ago. The Paranthropus lineage, with heavy jaws and large back teeth, lived alongside early Homo for more than a million years; a 2026 paper reported a 2.6-million-year-old Paranthropus jaw from Mille-Logya in the Afar region of Ethiopia (Alemseged et al., 2026).

Homo appears by 2.8 million years ago, in a jaw from Ledi-Geraru, Ethiopia (Villmoare et al., 2015). A 2025 paper reported Homo teeth at the same site dated to 2.78 and 2.59 million years and an unnamed Australopithecus at 2.63 million, and concluded that the two lineages lived in the Afar at the same time before 2.5 million years ago (Villmoare et al., 2025). Homo sapiens dates to 315,000 ± 34,000 years at Jebel Irhoud, Morocco (Richter et al., 2017). In January 2026 a paper described hominins from Thomas Quarry I in Casablanca, about 773,000 years old, which its authors place near the base of the lineage that led to Homo sapiens (Hublin et al., 2026).

Some groups are known from a single site and date; others from long stretches of time. Among the 18 groups with a date range, Homo erectus spans the most, from 1.89 million to 110,000 years ago by the Smithsonian’s dates, and Homo floresiensis the least, 40,000 years of skeletal remains on Flores (Exhibit 3).

The older record is African. Every species in this study dated to more than 2.5 million years was found in Africa, and nine of the eleven African sites of that age in this study’s data are in Ethiopia, Kenya and Tanzania. The others are Toros-Menalla in Chad and Taung in South Africa.

Brains

Upright walking came millions of years before large brains. The Laetoli footprints show bipedal walking 3.66 million years ago (Smithsonian), and Lucy’s species had a brain “usually less than 500 cubic centimeters,” in the Smithsonian’s words. A 2018 analysis of 94 fossil crania dated from 3.2 million to about 345,000 years ago found the signal across hominins “consistent with a gradual increase in brain size,” 64 or 88 percent of it from change within lineages, depending on the taxonomy used (Du et al., 2018).

Grouped by species, the averages in the same data run from 420 cubic centimeters for the single Australopithecus sediba cranium to 1,187 for the six Homo heidelbergensis crania. The 46 Homo erectus crania alone range from 546 to 1,300 (Exhibit 5).

Size did not rise in every line. Homo floresiensis, with skeletal remains on Flores dated to 100,000–60,000 years ago (Sutikna et al., 2016), was small-bodied, and jaws and teeth from Mata Menge show small hominins on the island about 700,000 years ago (Brumm et al., 2016).

Tools, fire and art

Stone tools are older than the oldest Homo fossil. A 2015 paper dated knapped tools at Lomekwi 3, Kenya, to 3.3 million years (Harmand et al., 2015), about 500,000 years before the Ledi-Geraru jaw. The Smithsonian dates the start of Oldowan toolmaking, with hammerstones, cores and sharp flakes, to at least 2.6 million years ago. At Nyayanga, Kenya, Oldowan tools from deposits dated 3.03–2.60 million years lay with butchered hippopotamus bones and two Paranthropus molars; the authors did not assign the tools to a maker (Plummer et al., 2023). Acheulean hand-axes follow by about 1.76 million years ago, by the Smithsonian’s count. Burned bone and ashed plants in Wonderwerk Cave, South Africa, about 1 million years old, are what its excavators call “the earliest secure evidence for burning in an archaeological context” (Berna et al., 2012).

The oldest dated rock art is a hand stencil in Liang Metanduno on Muna Island, Indonesia, with a minimum age of 67,800 years (Oktaviana et al., 2026). No human remains were found with it. Paintings in three Spanish caves dated to more than 64,000 years were attributed to Neanderthals in 2018 because they predate the arrival of Homo sapiens in Europe (Hoffmann et al., 2018); the dating is disputed (Exhibit 9).

Leaving Africa

Hominins were at Dmanisi, Georgia, shortly after 1.85 million years ago (Ferring et al., 2011), at Gran Dolina in Spain between 949,000 and 772,000 years ago (Duval et al., 2018), on the island of Flores by 700,000 years ago (Brumm et al., 2016), and on Luzon in the Philippines about 709,000 years ago, the earliest known hominin activity there (Ingicco et al., 2018). For Homo sapiens the dates are younger and more contested. Genomes from Ranis, Germany, place Homo sapiens in central Europe about 45,000 years ago (Sümer et al., 2024).

Two arrivals are disputed. At Madjedbebe in northern Australia, occupation was dated to about 65,000 years (Clarkson et al., 2017); a 2018 review concluded that an age above 50,000 years is unlikely to be valid (O’Connell et al., 2018). At White Sands, New Mexico, footprints were dated to 23,000–21,000 years from seeds of the aquatic plant Ruppia (Bennett et al., 2021). Critics argued the seeds could read too old because of a hard-water reservoir effect, and proposed no alternative age (Madsen et al., 2022; Oviatt et al., 2023). Pollen and quartz luminescence dates gave 23,000–21,000 years (Pigati et al., 2023), and lake-mud dates 22,400–20,700 (Holliday et al., 2025).

The other humans

Neanderthals, Homo floresiensis and Homo sapiens all lived within the last 100,000 years, and a fourth group, the Denisovans, was until 2025 known mainly from DNA. In April 2025 a paper identified a jaw from the Penghu Channel, between Taiwan and the mainland, as Denisovan from its proteins (Tsutaya et al., 2025). In June and August papers identified the Harbin cranium, at least 146,000 years old, as Denisovan from mitochondrial DNA recovered from dental calculus (Fu et al., 2025, Cell) and from its proteome (Fu et al., 2025, Science). The cranium had been described in 2021 as a new species, Homo longi (Ji et al., 2021). In September a paper placed the Yunxian 2 skull, about 1 million years old, in the Homo longi clade (Feng et al., 2025).

Living people carry part of that history. A 2024 study of more than 300 genomes spanning the past 50,000 years traced most Neanderthal ancestry in living non-Africans to a single extended period of gene flow between 50,500 and 43,500 years ago (Iasi et al., 2024); a second study, of the oldest Homo sapiens genomes yet sequenced, from Ranis and Zlatý kůň, placed it at about 49,000–45,000 (Sümer et al., 2024). A 2021 study found the highest Denisovan ancestry measured in the Ayta Magbukon of the Philippines, 30 to 40 percent above that of Australians and Papuans (Larena et al., 2021).

Where the dates disagree

Nine dates and claims in this study are disputed or have been revised. Four are disputes over evidence: White Sands, Madjedbebe, the Spanish paintings and burial by Homo naledi, which its finders claimed (Berger et al., 2025) and others reject (Martinón-Torres et al., 2024). One is a naming question (Harbin), and one an age not yet settled between two ranges (Penghu 1). Three are revisions by later dating, each older than the first estimate: Homo luzonensis from at least 67,000 to at least 130,000 years (Grün and Stringer, 2023), Omo I from 195,000 (McDougall, Brown and Fleagle, 2005) to at least 233,000 (Vidal et al., 2022), and Jebel Irhoud from about 160,000 (Smith et al., 2007) to 315,000 (Richter et al., 2017; Exhibit 8).

The breakthroughs

For 150 years the record grew by fossil: the Neander Valley in 1856, Java in 1891, Taung in 1924, Lucy in 1974. From 2010 it grew also by molecule. That year a draft Neanderthal genome showed that living non-Africans carry Neanderthal DNA (Green et al., 2010), and DNA from a finger bone identified the Denisovans (Krause et al., 2010; Reich et al., 2010).

The Allen Ancient DNA Resource, a curated compendium of published ancient genomes, held genome-wide data on more than 10,000 ancient individuals at the end of 2022 (Mallick et al., 2024) and on 17,634 in its release of April 13, 2026 (release v66.0).