Why do we humans eat meat now?

The story of people becoming ambitious carnivores began 65 million years ago.

The story of people becoming ambitious carnivores began 65 million years ago.

The dinosaur has just become extinct, along with more than half of the animal species on earth. In tropical forests spread across the planet, on soaring trees, our ancestors have just evolved. It was the first primates known: Purgatorius. It doesn't look like you or me, or even chimpanzees. It looks like a product between a mouse and a squirrel.

Purgatorius is a great talent climber - and a vegetarian. He gave up his ancestral insect's diet to come up with plentiful new fruits and fruits, giving himself a nest on the branches. For tens of millions of years, the descendants of Purgatorius have been associated with a plant-based diet. From small monkeys to big gibbons like gorillas, they all survive mainly on tropical fruits. About 15 million years ago, they were slightly more diversified, adding plant seeds and seeds to their meals, but were still true vegetarians.

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And then, about 6 million years ago, Sahelanthropus tchadensis set foot in the African primate system. With the birth of Sahelanthropus, our lineage seems to have since separated from its closest brothers, chimpanzees and bonobo gibbons. In the language of ancient anthropology, the word hominin refers to modern humans and all extinct species that are closely related to us - and Sahelanthropus is the first species. A dwarf creature with a tight face, a small brain, and almost straightened with two legs. It has smaller fangs and thicker enamel than its ancestors, suggesting that its diet needs more than chewing and crushing compared to Purgatorius, a fruit-only meal.

However, eating meat has not been discovered on our ancestors. Sahelanthropus may have eaten hard, high-fiber plants along with seeds and nuts. Later, some species of Australopithecus lived between 4 and 3 million years ago in the forest, riverside forests, and the seasonal floodplains of Africa did not touch meat either. The holes and scratches on microscopic surfaces on their teeth are caused by what they eat, suggesting that they have a homogenous diet with chimpanzees today: leaves, buds, lots of fruit, one some types of bugs, and even bark.

Does australopiths eat meat? Maybe. Just as chimpanzees today sometimes hunt colobus monkeys, our ancestors can also occasionally exchange dishes with smaller ones. However, the intestines of ancient hominin have not allowed them to have a meat diet. Their intestines carry the characteristics of leaf and fruit eaters, with a large cecum, a sac at the head of the large intestine. If a australopith is full of meat - for example, eat a few pieces of zebra steak for a while - it will twist the colon, appendicitis, flatulence, nausea, and possibly death. And despite those dangers, at 2.5 million years ago, our ancestors still became flesh-eaters.

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It seems that our bodies have changed gradually.

It seems that our bodies have changed gradually, first with attractive seeds and nuts, which are high in fat but low in fiber. If our ancestors ate them too much, such a diet would have to cause the small intestine to grow (where lipid digestion takes place) and contraction of the cecum (where the fiber is digested). This makes our intestines handle meat better. A grain diet is also a way for our ancestors to prepare for the carnivorous lifestyle: It has given them the tools to tear up prey. Some researchers argue that simple stonemasons for crushing grains can also be easily converted to animal bones and meat cuts. And so, 2.5 million years ago, our ancestors were ready for meat. They have enough tools to get meat and a body to digest it.

But there is a possibility; Having enough will and skill to get meat is another thing. So what prompted our ancestors to look at antelopes and hippos as a potential dinner? The answer, or at least part of it, may lie on climate change about 2.5 million years ago. As the rain becomes less, fruits, leaves, and flowers also decrease. Most rainforests are turned into sparse grasslands, with only a few plants that are good enough to eat while the number of herbivores is too much. During a dry period that lasts from January to April, our ancestors will have problems with food, and to eat enough, they will have to spend more energy and time.The ancient hominin stood before an evolutionary turn. Some species, like australopith, choose to eat large amounts of lower quality plants; Others, like the ancient Homo, sought meat. And australopith is finally extinct, but ancient Homo survived and evolved into a human being today.

Interestingly, while these ancient people chose to benefit from prairie herbivores and their meat, the ancestors of chimpanzees and gorillas were not. Perhaps one of the reasons is that they cannot walk on two feet. Finding meat will cost more, walking farther - and more energy - than eating grass and fruits. Moving with two feet will save energy more than the chimpanzee's cow type, and longer legs also dissipate heat better, preventing overheating and increasing durability. It seems that if Sahelanthropus or their ancestors did not straighten up six million years ago, the ancient Homo would not be able to equip such meat, and it would not be able to develop appetite for animal meat. - and yes we won't have steak or butter on dinner.

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Hominin is inherently omnivorous and knows the timing.

However, the question of what triggered the first breakthroughs in carnivorous species has yet to be answered. Perhaps some of our ancestors saw a sword tooth tiger eating antelope meat when walking. Or maybe it is a zebra that is dead, guts out of the flesh with meat, and they think, oh, why not try a piece?

Even purely herbivorous species such as deer or cows sometimes try meat if they have a chance. There have been records of cows eating chicken and eating dead rabbits, or bird-eating deer, and Duiker, a tiny African antelope, also hunting frogs. So it is hard to be surprised when our ancestors, who may have occasionally added to their diets of small monkeys' meat, saw the prairie animals as a new source of energy to supplement. .

Hominin is inherently omnivorous and knows the timing. If there's something edible in front of them, they'll eat it. About 2.6 million years ago, there was a lot of meat at the time. Just as Purgatorius took advantage of climate change and abundant new fruits, their descendants, ancient Homo, successfully adapted their diets to change with the environment. But this time, they found meat.