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Evolution of the Hand Axe: Meat Eater Min

The apes that are closest to human ancestors are herbivores.

Eating meat was an unlikely event for early humans. Archaeology tells us that more than 2 million years ago, the physique and height of human ancestors were only equivalent to today’s four or five-year-old children. Hunting is a fantasy.

Not only physical factors, but also technical conditions limit the efficiency of hunting. The spear as a hunting weapon only appeared 30,000 years ago.

In the long dark night before the dawn of human civilization, how did our ancestors eat? How does it evolve?

Less than 2 million years ago, during the long period of transition from Australopithecus to Homo sapiens, stone tools such as choppers and hand axes slowly appeared, making it possible to knock out bones and suck marrow, and to hunt.

Humans got rid of the status of scavengers in the lower reaches of the food chain and took the initiative to find meat to eat, thus opening a new chapter in the history of evolution.

On the morning of July 17, 1959, in Olduvai Gorge, husband Louis Leach felt unwell and stayed at the camp; wife Mary Leach ran alone into the field to continue her archaeological work.

The couple are both archaeologists from the University of Cambridge. For more than 20 years, they spent the most important time of their lives in Olduvai Canyon. Today, Mary is 47 and Louis is 56.

The Olduvai Gorge is located in northern Tanzania, East Africa, about 900 meters deep and 50 kilometers long. In the hearts of archaeologists, it may hide the key secrets of early human evolution. But the Li Qi couple never found the answer they were looking for.

In 1911, German entomologist Wilhelm Catwinkel chased a butterfly to the edge of a cliff and nearly fell. The entomologist carefully climbed to the bottom of the valley and found many fossil bones. This accidental discovery shocked the archaeological world, and naturally attracted the young and vigorous British archaeologist Louis Leach, and his later wife, Mary.

For now, Mary continues to dig in the wild, searching aimlessly. Coming to a slope within the canyon, she suddenly noticed a bone that appeared to be part of a skull. She dusted off the topsoil and saw “two large teeth set in the curve of her jaw”. On the way back to the camp, she was very excited and said, “I found him!”

A few weeks later, more fragments were excavated, and after restructuring, they found a relatively complete skull that they believed belonged to a human ancestor (later identified as an East African variant of Australopithecus). Li Qi published a paper saying that the owner of the skull lived 600,000 years ago. But not right. Scientists in the United States used the potassium-argon method to measure the volcanic ash in the riverbed and found that it can be traced back to 1.7 million years ago.

It was a time when human origins were older and more unknowable, and now, here comes the clue.

Li Qi and his wife did not go back there, and their son also joined the team. In 1963, they found another skull with a larger brain and more advanced shape, which was determined to have lived at least 1.78 million years ago. They named it “Homo Habilis”, which means able man, or clever man, which means skilled man. We now know that Homo sapiens was descended from Australopithecus and arrived in Olduvai Canyon about 1.9 million years ago.

More than 2 million years ago, the physique and height of human ancestors were only equivalent to today’s four or five-year-old children.

The restored skull of Homo Habilis

More importantly, they also found unusual stones on the spot, which were processed and showed a certain pattern of arrangement and combination. The stone was struck several times, forming a sharp edge. Later, these stones were thought to be early gravel stone tools.

The emergence of tools brings more stories. Like the bone in the hand of the orangutan in Kubrick’s film “2001: A Space Odyssey”, used for beating or as a weapon, and then thrown into the sky to bring some kind of intellectual epiphany, for the evolution of paleontology, The “epiphany” brought by the tool is a gleam of light in the endless darkness, faint, unreachable, even imperceptible, but significant enough.

Those stone fragments happened to be the “works” left by the capable people. Next to the stone tools, there are broken bone fragments of some extinct animal. Lewis speculates that stone tools were used to break animal bones so that humans could eat animal marrow.

Knock out bone marrow and bring about nutritional improvement, which means that the brain begins to evolve rapidly. In this sense, we can say that the story of humanity begins here.

Archaeologists now know that Olduvai Canyon is the perfect place to study early human evolution. Records of successive habitations by different early humans are preserved here, spanning more than 1.8 million years.

Stone artefacts are the main evidence for exploring the traces of these habitations, and they can also be used to spy on the evolution of their behavior and cognition. Of course, we can also learn how the evolution of stone tool technology will change the diet of early humans. And how you eat determines how humans evolve.

How to use the hand axe

Olduvai Canyon

The technical conditions of stone tools determine whether human beings are scavengers or hunters.

In 2015, the journal Nature published a study showing that the earliest stone tools dated to 3.3 million years ago and were unearthed in Kenya, Africa. The stone tools are very primitive, and some features of hammering and smashing are vaguely visible.

A large number of stone tools dating back 2.5 million years were unearthed in Olduvai Canyon, mainly gravel and rock blocks, with only traces of simple hammering. In 1961, Cambridge University archaeologist Grahame Clark proposed a model of early human technological evolution in his book “A Summary of the Prehistory of the World”. He called the stone technology of this period the Olduvian technology.

Of course, Olduvian tools are not entirely unearthed in Olduvai Canyon. The term refers to a technical form, and in many sites in Africa or outside Africa, there are also stone tools that are close to Olduvian technical characteristics.

Among Olduvai tools, the most typical product is a smasher, usually with cracks or dents, used to break nuts or bones. In addition, there are relatively sharp scrapers. Archaeologists have observed subtle changes on the stone blades and can infer that they are used to scrape wood, cut animal skins, etc.

The technical conditions of stone tools determine whether human beings are scavengers or hunters. Before the age of Olduvian tools, humans were the scavengers at the end of the food chain. Ferocious animals such as lions, vultures, and hyenas will enjoy their prey first. When humans are eligible to play, in most cases, the “prey” has become carrion, or even bones without meat.

Fortunately, Olduvai tools have greatly improved the efficiency of scavenging.

In December 2021, Harvard archaeologist Manuel Dominguez-Rodrigo and his team published a paper. They studied a large number of 1.8-million-year-old feline skeletons, also unearthed from Olduvai Canyon. Using artificial intelligence, they attempted to identify traces of human interaction with these animals.

They found that no meat residue was found in the cut marks of the proximal radius of these animals. This shows that the meat on this part was obtained in the middle and early stages. This reinforces the conclusion that opportunistic passive foraging was rare 1.8 million years ago. Instead, more evidence suggests that confrontational access to meat has emerged.

To do this, there must be more advanced technology.

Opening the “Summary of World Prehistory”, we found that the evolutionary tree of mankind has quietly come to the era of Homo erectus. Around 1.7 million years ago, Olduvian tools evolved into Asheli tools, and a new tool that was more conducive to meat acquisition, the hand axe, appeared.

Now, let’s briefly return to the story at the beginning of the article.

Archaeologist Louis Leach, who was less than 30 years old, made an amazing discovery not long after he came to Olduvai Canyon. He unearthed a hand axe, a solid block of green lava, machined on both sides, in finely polished symmetry, with sharp, all-around cutting edges.

In the hand, the high fit is a testament to the craftsmanship.

The hand axe is 1.2 million years old and later collected in the British Museum. In 2010, the British Museum and the BBC launched “The History of the World in a Hundred Collections”, the third item.

The Olduvian Hand Axe represents a leap in human technology. Although it is called the Olduvian Hand Axe, according to the Clark model classification, the Olduvian Hand Axe is actually a masterpiece of Acheul technology, created for Homo erectus. In addition to this, typical Acheulean tools are hand picks and thin-bladed axes.

The craftsmanship of the Asheli hand axe is complex. It is not knocked out at one time, but formed by long-term learning, perfection, and repeated use of skills. For example, in experiments that reproduced hand axe making in neuroscience, the brain activity of volunteers while making them overlapped with our brain activity when we spoke. This could mean that while hammering these hand axes together, humans learned how to speak.

Larger and heavier than Olduvian tools, Ashley tools helped early humans hunt because of their chiseled edges.

In the Olorgesailie site group in Kenya, a large number of densely distributed characteristics of the Acheuli handaxe appear. The assemblage of hand axes and other stone tools also varied between sites. This means that the early hand axe population has the ability to plan ahead, foresee survivability, and know how to reserve hand axe to meet future needs.

We will find that the appearance of the hand axe not only made hunting possible, but also helped Homo erectus to escape the constraints of the environment. As the climate in Africa became drier, Homo erectus with hand axes began to travel far. They skinned animals for cover, cut down branches to make fires, coped with heat and cold, provided food and clothing, and even built shelter.

Most culture, stone scraper for cleaning and processing leather

Gesher Benot Ya’aqov site in Israel

Early Homo sapiens (Neanderthal) skull reconstruction, Neues Museum, Berlin

The Gesher Benot Ya’aqov site in Israel, located in the Levant region, is considered to be the first stop of Homo erectus out of Africa, in the transitional stage between the early and middle Pleistocene, about 800,000 years ago. Here we can see traces of more sophisticated hand axe techniques.

There are a large number of flint waste fragments in the ruins, which are related to the hand-axe repair. At the same time, there are also a large number of mammal fossils, of which the skeleton of the deer is the most complete. This may be the result of humans returning the carcasses to their dwellings intact after hunting the fallow deer. In addition, there are more than 30,000 fish fossils, and nuts with high nutritional value such as acorns, olives, and almonds are also abundant. The amount of these edible items unearthed is more than 10 times that of natural sections. This proves that the dietary life of Homo erectus entered a state of abundance.

Acheuli tools lasted until 300,000 years ago and entered the third stage – the Moste culture, which was created by early Homo sapiens (Neanderthals) and is characterized by entering the stage of aesthetic budding.

Looking back, from a technical point of view, the hand axe and Acheuli tools represent the beginning of modern human beings, and also completely bring human beings into the carnivorous stage. The effect of eating meat is intuitive: high-fat, high-protein nutrient intake promotes physical development and brain evolution. Brain evolution has accelerated tool innovation in a virtuous cycle.

Unlike Homo sapiens, Homo erectus had a brain volume of more than 1000 milliliters and an average height of nearly 160 centimeters. The human ancestors at this time were no longer dwarfs hiding behind various beasts.

But meat also shapes us in another sense. The apolipoprotein E4 dual gene appeared 1.5 million years ago, which happened to be the stage when hand axe technology appeared and when humans entered the meat-eating stage.

Apolipoprotein helps humans digest fatty foods, but modern medicine has also shown that this gene is also directly associated with some deadly aging diseases, such as Alzheimer’s disease, such as stroke.

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