Who was the ancient human with the largest brain capacity in the Middle Pleistocene? The answer is revealed!

Human brain capacity is closely related to intelligence level. How big was the brain capacity of ancient humans? Scientists tell you the answer.

Researchers from the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences and other institutions have for the first time restored a relatively complete skull of Xujiayao man from the late Middle Pleistocene, and successfully calculated the brain capacity of Xujiayao man.

The relevant research results were published online in the international professional journal Journal of Human Evolution.

Using CT technology and the mirror principle, researchers have restored a relatively complete skull of the Xujiayao people for the first time, providing important specimen materials for observing the overall morphological characteristics of the Xujiayao people. Combining the endocranial mold and the formula method, it is estimated that the cranial capacity of the Xujiayao people is about 1700 cm3, which is close to the cranial capacity of the Xuchang people reported previously (1800 cm3), but is nearly 60,000 years earlier than the Xuchang people. It is the "big-headed man" with the largest cranial capacity discovered in the Middle Pleistocene so far.

Xujiayao man skull fossil fragments and its restored skull and endocranial mold (Photo courtesy of Wu Xiujie)

A1-3: PA1486, lateral, top, and medial views of the occipital bone; B1–3: PA1490, lateral, medial, and top views of the right parietal bone; C1–4: PA 1498, lateral, mesial, lateral, and inferior views of the left temporal bone; D1-6: top, front, left, right, posterior, and inferior views of the 3D virtual reconstruction of the skull; E1-3: top, posterior, and right lateral views of the 3D virtual reconstruction of the endocranial model.

The Xujiayao human fossils were discovered at the Xujiayao site (also known as the Houjiayao site) at the border of Shanxi and Hebei provinces between 1976 and 1979. The fossils are relatively fragmented, including 18 skull fragments and 3 loose teeth. These fossils represent more than 10 individuals. "Based on the species of mammals unearthed with them, the burial conditions of the strata and various dating, researchers have determined that the Xujiayao people lived in the late Middle Pleistocene, about 200,000 to 160,000 years ago," Wu Xiujie introduced.

Xujiayao Man Site (left) and the restored skull of an ancient human fossil (right)

Previous studies have shown that the Xujiayao people are a very special group of ancient humans. Their physical characteristics show a mixture of East Asian Homo erectus, European Neanderthals and early modern humans of the late Pleistocene. Their evolutionary position has been successively classified as early Homo sapiens, Neanderthals, late archaic humans, Denisovans and unknown populations. The growth and development pattern of their teeth has entered the ranks of modern humans.

It is generally believed that the brain capacity of ancient humans in the Pleistocene increased with the geological age. For example, the brain capacity of Australopithecus was 404-530 ml, the brain capacity of Homo habilis was 510-752 ml, the brain capacity of Homo erectus was 600-1251 ml, the brain capacity of the archaic Homo sapiens in the Middle Pleistocene was 1100-1450 ml, and the brain capacity of early modern humans and Neanderthals in the early Late Pleistocene increased to more than 1500 ml.

However, "the discovery of new fossils in recent years has changed people's traditional cognition." Liu Wu, a researcher at the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, said that the Naledi people discovered in Africa in 2013, which are about 300,000 years old, had a brain capacity of only 560 ml; the Flores people discovered in Indonesia in 2003, which are 100,000 to 50,000 years old, had a brain capacity of only 400 ml; the Xuchang people reported in 2017, which are 125,000 to 105,000 years old, had a cranial capacity of 1,800 ml.

"Although some scholars have proposed various hypotheses for the drastic changes in the brain volume of some Pleistocene ancient humans, such as food diversity, changes in environmental climate, and the complexity of human behavior, many hypotheses are not convincing," Wu Xiujie explained.

"Our research found that the skull morphology of the Xujiayao people and the Xuchang people is very similar. Both have big heads and low skulls, and both have the inner ear labyrinth pattern unique to Neanderthals. The two may be the same population. Considering that the Xujiayao people lived earlier than the Xuchang people, it is possible that the Xujiayao people are the direct ancestors of the Xuchang people!" Wu Xiujie said that around 300,000 to 100,000 years ago, a type of "big-headed people" with special physical characteristics may have lived in China.

In recent years, some international paleoanthropologists have proposed hypotheses about the Denisovans, believing that the Denisovans may have existed in China's fossil records, especially the Xuchang Man and the Xujiayao Man. "If this is true, the Denisovans' cranial capacity may also be very large," Liu Wu said.

【Extended Reading】

The Xujiayao site is located 1.5 kilometers southeast of Xujiayao Village, Gucheng Town, Yanggao County. It is 600 meters long from north to south and 200 meters wide from east to west. It belongs to the Middle Paleolithic Age.

The remains of Xujiayao people's civilization are an important part of Chinese civilization. Datong Lake has long been dried up in the changes of the earth, and together with the surrounding volcanoes that have been extinguished for millions of years, this land has been transformed into a basin. However, the human fire that originated from the lake has continued to cultivate and live, and has been passed down to this day.

The Nihewan Basin where Xujiayao Village is located spans across Shanxi and Hebei provinces. The Sanggan River meanders from southwest to northeast, running through the entire basin. On the north bank of the Sanggan River, there is a small tributary called Liyigou. On the west side of the gully, there is a small village called Xujiayao Village with less than 100 households. Through excavation, the true appearance of the "Xujiayao people" has gradually emerged.

Experts have verified that the Xujiayao people are descendants of the Peking Man, who migrated westward about 100,000 years ago and settled here after encountering the Datong Lake. The Xujiayao people lived more than 100,000 years ago, inhabiting the shores of the Datong Lake and leading a life of fishing, hunting and gathering.

The animal fossils unearthed at the Xujiayao site include ostriches, pikas, zokors, voles, wolves, tigers, elephants, rhinos, wild horses, wild donkeys, wild boars, giant deer, red deer, sika deer, gazelles, goitered gazelles, and primitive cattle. The largest number of fossils are wild horses, antelopes, and rhinos. At least 300 horse materials have been obtained, and most of them are young and old individuals. Many animal bone fossils that have been burned were also found.

According to the analysis of animal groups and plant pollen, the average annual temperature in the Xujiayao area was slightly lower than it is now, with cool summers and severe winters, little precipitation and dry air. This was a mixed area of ​​grassland, shrubs and forests. According to anthropological research data, from the healing of bone sutures on the fossil skull, the degree of tooth wear and the law of permanent teeth replacing milk teeth, it can be determined that among the "Xujiayao people" there were 7-year-old children, teenagers, young people in their twenties and thirties, and elderly people over fifty.

"Xujiayao Man" skull fossil

Ji Lianhai, a historian who has appeared on CCTV's Lecture Room many times, specially taught the section on "Xujiayao Man" when he was a guest at Datong's "Citizens' Lecture Hall". His point of view is that humans not only came from the Olduvai Gorge in East Africa, but also most likely from Nihewan in China. The "Xujiayao Man" site tells people that this is one of the birthplaces of Eastern humans and the starting point of the long evolutionary journey of the ancestors of Northeast Asia. Compared with the Olduvai Gorge in East Africa, which is known as the "cradle of mankind", the value and status of this place are no less.

Comprehensive sources: Science and Technology Daily, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Shanxi Provincial Cultural Relics Bureau, Datong Evening News, etc.

Some of the pictures in this article are provided by the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy