After checking into another legendary oasis, Bi Fang led Alpha and continued to move eastward along the canyon.

The well-fed West African crocodiles lay quietly on the shore, lazily opening their mouths, enjoying the warm sunshine. There were several pigeon-sized animals staying in the water behind them, with four colors: black, white, gray, and light yellow.

feather bird.

These birds are colorful and very eye-catching when viewed from a distance.

He stepped into the water with his long feet, making tiny ripples, and caught the small fish in the river. Two of them seemed not to be satisfied. After searching for a while, they set their target on the West African crocodile beside them. They jumped around on the shore and jumped suddenly.

Put it in your mouth, lower your head and start eating.

[What kind of bird is this? It looks so beautiful]

[Hiss, isn’t it afraid that the crocodile will eat it?]

【I’ve seen this, Toothpick Bird!】

[I seem to have read in that article that this is eating the meat residue from the crocodile's mouth, and it can also help clean the mouth. The two have a symbiotic relationship, so the crocodile will not eat birds]

"Uh" Bi Fang scratched his eyebrows, "This is probably fake."

【Ah this】

【Is it fake?】

[It’s over, I’m going to be slapped in the face by Fang Shen]

"The scientific name of the toothpick bird is the Egyptian plover. The statement about the mutually beneficial symbiosis between it and the crocodile comes from the records of an ancient Greek writer named Herodotus, in a book called "History"."

"This book records what Herodotus saw and heard during his travels, as well as the history of the Persian Achaemenid Empire. It is the first prose work to be completely handed down in the history of Western literature."

"There is a record in it about what you call the 'toothpick bird'. The general idea is that, according to Herodotus, a Nile crocodile would lie on the shore, open its mouth, and let a bird named 'trochilus'

Fly into its mouth and help the crocodile remove the carrion and leeches from its mouth."

"But from a biological point of view, crocodiles do not need teeth cleaning. They are not like mammals, whose teeth are broken and cannot be replaced."

"Each crocodile tooth is composed of three parts: a functional tooth, a replacement tooth and a dental plate. The stem cells in the dental plate ridge can develop into replacement new teeth. It is the special structure of the crocodile teeth that allows the new teeth to replace the functional teeth.

The process of maturing teeth proceeds smoothly.”

"Secondly, the crocodile's teeth are widely spaced and cannot hold food debris."

The crocodile's teeth are cone-shaped, and the gaps between the teeth are also cone-shaped. The main function of the teeth is to capture and kill animals, and then swallow them whole instead of chewing them. They will not chew them carefully and then swallow them, so there are no

Meat residue will not be stuffed with meat.

"Even if there are still bacteria on the teeth, it can't be solved by a bird. In other words, the bird will basically not get much benefit from being in the crocodile's mouth."

"The most important thing is that except for Herodotus who saw this phenomenon more than two thousand years ago, no other scientist has observed it."

"The photos of the Egyptian falcon picking the teeth of the crocodile that are circulating on the Internet are actually digital reconstructions based on Herodotus's description."

For many years, people have believed in the legend of the toothpick bird, and regarded the friendship between the toothpick bird and the crocodile as an example of mutualistic symbiosis between animals.

But as time goes by, more and more people have raised questions. The biggest question is that more and more people are traveling to the African continent, including many photographers or photography enthusiasts.

If they saw an interesting scene of a bird getting into the mouth of a crocodile, they would take this precious shot anyway.

However, there is not a single such photo.

In addition, many scientists who have visited Africa have never seen this strange phenomenon.

“In the more than 2,400 years since Herodotus’s death, only two zoologists claimed to have seen a toothpick bird fly into a crocodile’s mouth to eat. Unfortunately, their stories did not have a specific time or place.

, there is no real evidence and it is unconvincing."

"Later, in order to uncover this ancient mystery, Mr. Howell, an ornithological expert from the University of California, made a special trip to the Gambella region of Ethiopia in Africa for two and a half months of investigation."

"During the two-and-a-half-month inspection, Professor Howell worked tirelessly, leaving early and returning late, and discovered many interesting living habits of the Egyptian plover, which no one had ever known before. But he had never seen it.

To the Egyptian plover catching insects in the mouth of the crocodile.”

"Finally, the biologist Thomas Howell wrote a book in 1979. The book basically stated that he himself had never seen this phenomenon. Some authors in history claimed that they had seen this phenomenon.

But these authors are not particularly reliable.”

"According to his research, even if the story of the crocodile and the toothpick bird being good friends described by Herodotus is true, it is still a very rare phenomenon. This is definitely not the main food source of the bird, so the crocodile and the Egyptian hawk are not symbiotic.

relation."

"That is, it should not be viewed as an example of mutualism between animals."

"This is an individual behavior and cannot become a commonality of a species."

"We were lucky to see the toothpick bird enter the crocodile's mouth."

[It was really hard to see someone I knew, but in the end I was slapped in the face by Fang Shen. It was really difficult]

[It’s really hard to survive in the wilderness. I really don’t know anyone. It’s not easy to get to know one, but the result is still wrong]

Bi Fang laughed.

[Then why doesn’t this crocodile eat the toothpick bird?]

[Yes, what is this bird doing in the crocodile’s mouth?]

"Probably eating some parasites or something."

Bi Fang stared at the crocodile for a few times.

"All animals have one characteristic, which is that they stop hunting when they are full."

"When hunting, crocodiles will not lie down with their mouths open. Instead, they will float quietly underwater, with only their eyes and nostrils exposed. When they lie down with their mouths open, it means they are full and will not hunt anymore, even if birds

It jumps around its mouth and won't hunt for food."

"This is just like those crocodile performances. People often put their hands or heads into the crocodile's mouth to gain applause through such a thrilling scene. Before starting such a performance, the crocodile has definitely been fed.

I’m full.”

"Besides, the reaction and movement of crocodiles are much slower than those of birds. They can't eat if they really want to, so they let them go. But it's not certain whether they will eat."

As soon as he finished speaking, everyone heard a loud clash of teeth.

The originally motionless West African crocodile suddenly closed its upper and lower jaws. Only one of the two toothpick birds escaped, while the other one was bitten without any suspense and swallowed in a few bites.

With one successful blow, the West African crocodile quickly changed direction, swam towards the river and disappeared.

Not long after, everything returned to calm, and the few crocodiles nearby did as they pleased, as if nothing had happened.

[Hiss, Fang Shen was actually right]

[It’s true that people die for wealth and birds die for food]

【Oh my god, it's amazing】

Several toothpick birds were pecking at a small fish together.

As we go deeper and deeper, the pollution level of the Blackwater River begins to lessen. It is no longer black but light gray. There are fewer and fewer wild camels to be seen, and more West African crocodiles are replacing them.

The densely packed crocodiles on the shore made the audience's scalp numb, especially when Bi Fang almost brushed past them, it reached its peak.

[Why do I feel like there are more and more crocodiles]

【This is almost out of reach】

【Scared, too scary】

[Fang Shen is also too courageous]

"This is a normal phenomenon. Strictly speaking, the overlap between the lives of West African crocodiles and camels is not high. West African crocodiles do not survive by eating camels, but basically rely on eating fish. Therefore, the fewer camels, the number of crocodiles will increase.

Because where there are few camels, there are more fish.”

Bi Fang looked at the river and explained briefly.

Excessive pollution will make the fish in the river scarce, reducing the rations of West African crocodiles, and they will naturally not come close to the gathering places where the camel feces pollution causes the river water to turn black.

Situations like this are not uncommon in Africa, such as the Mara River, which is one of the water bodies where hippos gather. During the dry season, there will be many hippos crowded into small lakes.

They excrete 8.5 tons of feces every day. Too much feces accumulates, making the environment of these small lakes very harsh.

The dry season is okay, because the area of ​​​​the water area is not large, and it only affects the surrounding area, but in the rainy season, the water areas are connected and turn into a big river. The feces that has not had time to be decomposed by microorganisms will be washed away by the river water and float to other places.

Everywhere.

[I feel a little sick]

[It’s too harsh, so it’s a yes]

【Want to visit】

[A bit hanging]

【What kind of manure making machine】

Feces accumulated at the bottom of the water for a long time will produce gases such as methane, hydrogen sulfide, and ammonia through microbial fermentation, resulting in a significant reduction in the oxygen content in the water, resulting in a large number of fish deaths in the river.

When the rainy season comes, many dead fish bodies will appear on the surface of the Mara River. These suffocated fish have become a rather special phenomenon.

And this phenomenon is still a vicious cycle. The death of fish in the river will increase the accumulation of decay, which will cause the river's purification ability to fail to keep up with the production rate of pollutants, causing it to be further polluted, making it increasingly unsuitable for the survival of living things.

If it weren't for the Nile crocodile inside, unlike the West African crocodile, which basically survives by eating fish, it would almost become extinct.
To be continued...