The overall direction of the Tao River runs from north to south, but the winding river cannot accurately identify the actual distance traveled, so Gu Guo can only determine the time by the sun and estimate the general direction with the stars.

They had been sailing for five days, and the river was much wider than when they first set off, Gu Guo was not sure whether the Tao River was a tributary or the mainstream, if it was, their end would be the sea, but he preferred that the Tao River was a tributary of a larger river, after all, there were very few rivers with an estuary that were only a few hundred meters wide.

After the inaugural test, it took five times longer to return home, which meant that they had to return on the 10th day.

Of course, it is also a way to put a birch bark boat down to the shore to collect food, but for safety reasons, Gu Guo still decided that this trip was just to find out the number of tribes on the bank of the Tao River, and as for disembarking from the boat to investigate, wait until the fleet is formed in the future and has more than a hundred or ten people.

In the past five days, except for the Yangya tribe that arrived the next day, they have encountered no less than twenty tribes one after another, basically all of them belong to the level of their own tribe that Gu Guo has not yet crossed over—living in caves.

The further south he went, the more backward the tribe he encountered, Gu Guo estimated that he was now thousands of miles away from his tribe in a straight line, when he finally saw the people of a tribe, those primitive people whose faces were covered with various colors of paint, put down the stone spear in their hands, knelt down to worship at the top of their sailboat, Gu Guo clearly saw the angular lines on the stone spear.

That's a stone tool!

This special mother's is not the same as my own estimate!

Along the way, no tribe is more advanced than the Sheeptooth Tribe!

The undying Gu Guo sailed on the Tao River for another five days, but he was greeted by dense primeval forests one after another.

On the last day of his journey south, Gu Guo decided to go ashore to take a gamble, at least he wanted to make sure that there were no traces of human activity two thousand miles away.

Fixing the sailboat not far from the river bank, Gu Guo and the others put down three birch bark boats and rowed to the river bank.

The reeds on the bank of the river had already pulled out their buds, and the birch bark boat was hidden among the lush reeds, and the group went ashore in full gear.

The shore is full of wild grasses as high as calves, which is a good choice to use as feed for wild boars, but at this time, the eyes of the clansmen are all vigilant around, and only Gu Guoguo, who is standing in the center of the crowd, has the leisure time to observe the surrounding environment and landforms.

Desolate.

It's not the barren desolation of Mars, it's the lifeless desolation of no people.

The weeds around are all straight upwards with no sign of lodging, and the trees in the distance are still unexplored: vines and weeds grow wildly on the branches, and the dense canopy blocks the sun, looking like the Black Forest in the game Minecraft.

Gu Guo learned in a book in his previous life that the woolly bear scientist proposed that in the late Paleolithic Age, 40 million square kilometers of land supported about 3.2 million people in the world, and before he crossed over, the number of primitive people in the Neolithic Age in the world would probably not exceed 10 million.

And he went all the way south, and according to the density between tribes and the frequency of encounters with tribes by the river, at least 20,000 people were supported on the more than 100,000 square kilometers of land in the Tao River basin.

This comparison seems to make sense.

Is this really just an ordinary primitive world? The so-called battlefield of Gaia encountered only one enemy of the same level (Neolithic) (James)?

In the Tao River Valley, are there no more advanced groups than their own tribes?

The south has been determined, but what about the north? Where did the yellow-haired tribe led by James come from?

Gu Guo found that the wider the scope of his exploration, the more problems he had.

A group of people wandered outside the forest for a while, picking two baskets of wild fruits in the bushes, separated by a latitude of thousands of kilometers from north to south, resulting in many broad-leaved plants here, which he had only seen in systematic botanical knowledge, and the surrounding tribesmen did not recognize a few.

"Goo, let's not go any further." With the hunter's intuition, Birch, who was standing at the front of the team, was the first to speak.

He pointed to the edge of the forest as far as the eye could see, where the weeds were waist-high, and the yellow and green stems and leaves moved slowly in the breeze, and the intertwined shadows disrupted the vision.

"There may be a long-toothed tiger over there, let's not go there."

"Toothed tiger?" Gu Guo asked in a low voice, he immediately thought of the saber-toothed tiger, but there had not been a double-edged sword in this era, so words such as swords would not appear in the name of animals.

"Yes, although we have bows and spears that can kill one or two long-toothed tigers, they are much more difficult to deal with than those two wolves! If the tribesmen were injured, they would not be able to survive the return of the sailboat for treatment. Pigskin added.

"What does a long-toothed tiger look like?" Gu Guo asked.

The group lowered their bodies and slowly retreated, not running with their backs to the grass at this time, only the prey would open its backs to the predators.

"This thing has long teeth, probably longer than the tip of a bronze spear." Birch gestured with his finger and replied, "At least half a birch bark boat is as long as you." ”

"The cave where we met earlier is said to have been the territory of the long-toothed tiger, but it was later driven away by other tribesmen, and I only saw the bones of a long-toothed tiger when I was a child."

The abundance of food and the threat of the long-toothed tiger lurking in the shadows forced Gu Guo to return.

After the beginning of spring, the warmer and warmer temperatures were not suitable for storing fruits and vegetables, and Gu Guo only brought a few days' worth when he set sail, so on the way back, people more or less began to have symptoms such as constipation caused by lack of vitamins.

But he was not too worried about the deterioration of his condition and that of his people, and after more than forty days of zigzag sailing, he could already see wisps of smoke behind the walls.

It is believed that under the conditioning of meat and vegetables, the clansmen can quickly adjust their physical state.

During the time that Gu Guo was away, Gui had already led his people to complete the construction of the aerial canal, an extra-long slope of two kilometers long, which had been connected to the rotating waterwheel, and the water was transported from the river bank to here, and a freshly dug pond began to accumulate water from the Tao River.

Xiao Feng and Huaihua put a lot of crucian carp in the pond, according to Gu Guo's thinking, the boar can be raised, then the fish can also be raised in the pond, and when the next winter, the water of the Tao River freezes, and the people can go to this pond, smash the ice, and catch fish in the water.

Gu Guo had to admire Xiao Feng and Huaihua's brains, after learning knowledge and broadening their horizons, they were really much more enlightened than when they were illiterate.