Peking Man: The Zhoukoudian Fossils and Their Wartime Loss

Peking Man is the popular name for a remarkable collection of Homo erectus fossils excavated at Zhoukoudian, a limestone hill about 50 kilometres south-west of Beijing, between the 1920s and 1937. The bones of roughly 40 individuals, who lived there in the period between about 770,000 and 400,000 years ago, made Zhoukoudian one of the richest early human sites in the world. Then, in December 1941, almost all of the original fossils disappeared in the chaos of the Pacific War, and they have never been found.

Background: dragon bones and a promising hill

For centuries Chinese apothecaries sold “dragon bones”, fossil teeth and bones ground into traditional medicines. In the early 20th century Western scientists began to follow these fossils back to their sources. One of them was the Swedish geologist Johan Gunnar Andersson, an adviser to the Chinese government, who visited Zhoukoudian in 1918 and returned in 1921 with the Austrian palaeontologist Otto Zdansky and the American Walter Granger.

Local quarrymen led them to a fossil-rich fissure in the hill called Longgushan, “Dragon Bone Hill”. Andersson noticed pieces of quartz, which does not occur naturally there, and suspected that early humans had carried it in to make tools. Zdansky dug at the site in 1921 and 1923, and among the material shipped to Uppsala in Sweden he identified two human-like teeth. Their discovery was announced in Beijing in October 1926.

The excavations at Locality 1

The Canadian anatomist Davidson Black, professor at the Peking Union Medical College, secured funding from the Rockefeller Foundation for large-scale excavations at the site, now known as Locality 1. In October 1927 the Swedish palaeontologist Birger Bohlin found a well-preserved lower molar. On the strength of this single tooth, Black boldly named a new genus and species, Sinanthropus pekinensis, the “Chinese man of Peking”.

His gamble paid off. On 2 December 1929 the young Chinese archaeologist Pei Wenzhong, digging late in the season, found a nearly complete skullcap embedded in the cave deposits. It made headlines around the world. The work was organised from 1929 by the Cenozoic Research Laboratory of the Geological Survey of China, with the French Jesuit palaeontologist Pierre Teilhard de Chardin among the collaborators.

Black died suddenly at his desk in March 1934, and in 1935 the German anatomist Franz Weidenreich took over the scientific study. In November 1936 Jia Lanpo, who had succeeded Pei in charge of the digging, uncovered three more skullcaps within a few days. Excavation stopped in 1937 when the Japanese invasion of China reached the area.

What the fossils showed

By 1937 the excavators had recovered around 200 human fossils, including six fairly complete skullcaps or crania, many skull fragments, around 15 lower jaws, roughly 150 teeth and a handful of limb bones. They are usually attributed to some 40 individuals of both sexes and all ages. Alongside them lay tens of thousands of stone artefacts, mostly simple flakes and choppers of quartz, and the bones of animals such as deer, horses, rhinoceroses and a giant hyena, Pachycrocuta.

The skulls were long and low, with thick walls, heavy brow ridges and a sloping forehead. Brain sizes ranged from roughly 900 to 1,225 cubic centimetres, around three-quarters of the modern average. These features closely matched the fossils found in Java by Eugène Dubois in 1891, known as Java Man. From the 1950s both groups were merged into a single species, Homo erectus, and Peking Man is now often written as Homo erectus pekinensis.

Fire, cannibalism and other debates

The early excavators described thick layers of ash, burned bones and charred stone, and for decades Peking Man was cited in textbooks as one of the earliest users of fire. In 1998 a team led by Steve Weiner argued in the journal Science that much of the so-called ash was in fact water-laid sediment and that there was no clear evidence of hearths. Later studies identified burned bone that does point to fire at the site, but whether the people of Zhoukoudian controlled it, rather than exploiting natural fires, remains debated. The wider question is explored in control of fire by early humans.

Weidenreich also noted that many skulls were broken and that the base of the skull was often missing, and he suggested the people had practised cannibalism. Later researchers, notably Noel Boaz and Russell Ciochon, re-examined the casts and argued that much of the damage was made by large hyenas, which used the cave as a den and gnawed the human remains. Most specialists now see hyenas as a major part of the story, though humans clearly also lived in and around the cave.

The disappearance of 1941

After Japan occupied Beijing in 1937, the fossils remained in a safe at the Peking Union Medical College, an American-funded institution. Weidenreich, aware of the danger, had detailed plaster casts made and prepared thorough descriptions and photographs before he left for the United States in 1941. As relations between Japan and the United States worsened, Chinese and American officials agreed to send the originals to America for safekeeping.

In late November or early December 1941 the fossils were packed into two crates and handed to a US Marine detachment, which was to take them by train to the port of Qinhuangdao and onto the liner SS President Harrison. On 7 December 1941 Japan attacked Pearl Harbor, the Marines in northern China were taken prisoner, and the ship never arrived. What happened to the crates is unknown.

Theories abound: that the bones were buried near Qinhuangdao, seized by Japanese soldiers, sold, or lost at sea. Searches have been made at various times, including by Chinese authorities and researchers in the 2000s and 2010s, and rewards have been offered, but no verified trace has emerged. Only a few teeth from Zdansky’s work kept in Sweden, and a small number of fragments recovered at Zhoukoudian after the war, including skull pieces found in 1966, survive as originals.

Dating the cave

Dating Locality 1 has been notoriously difficult because the cave filled up over a very long time. Older estimates, based on animal fossils and several laboratory methods, placed the human remains between about 500,000 and 230,000 years ago. In 2009 a team led by Shen Guanjun used aluminium-26 and beryllium-10 burial dating on quartz from the lower layers and obtained an age of about 770,000 years, with an uncertainty of around 80,000 years.

The upper fossil-bearing layers appear to be considerably younger, perhaps around 400,000 years or less, so the human presence at Zhoukoudian probably spanned hundreds of thousands of years, though not necessarily continuously. A separate part of the hill, the Upper Cave, contained remains of modern humans from the last Ice Age, tens of thousands of years old.

By the numbers

Timeline

• 1918: Johan Gunnar Andersson first visits Zhoukoudian.
• 1921: Andersson, Otto Zdansky and Walter Granger identify the fossil fissure at Dragon Bone Hill.
• 1926, October: Zdansky’s two human teeth are announced in Beijing.
• 1927, October: Birger Bohlin finds a molar; Davidson Black names Sinanthropus pekinensis.
• 1929, 2 December: Pei Wenzhong discovers the first nearly complete skullcap.
• 1936, November: Jia Lanpo finds three more skullcaps.
• 1937: Excavations stop after the Japanese invasion reaches the area.
• 1941, December: The packed fossils vanish after the attack on Pearl Harbor.
• 1987: The Peking Man Site at Zhoukoudian becomes a UNESCO World Heritage Site.
• 2009: Burial dating places the lower layers at about 770,000 years old.

Why it matters

Peking Man gave the world its first large sample of Homo erectus and showed that early humans had lived in northern China, in a cold, seasonal climate, for a very long time. Even though the originals are lost, Weidenreich’s casts remain a scientific reference. The story is also a reminder of how fragile the record of human evolution is, and how war can destroy evidence that took hundreds of thousands of years to preserve.