I believe that many people have seen the famous scene of hippotamus defecation in funny videos, and this guy often makes such "indecent" moves when people go to the zoo to see it, and it is difficult not to doubt whether they are intentional.
Of course, humans are only facing the visual impact of the hippopotamus's sudden "defecation", and the situation of other creatures living in the same waters as it is actually more difficult.
Hippopotamus's "fecal attack"
It is reported that every year, thousands of fish are suffocated by the excrement of the river horse. What's going on here? How terrifying is hippopotamus droppings? Let's take a look.
Hippopotamus feces kill schools of fish
The most impressive thing about hippos is their "blood basin mouth", which can not only swallow watermelon raw, but also have a rather amazing bite force. As the third largest animal on land, the hippopotamus's ability to dry food is still very strong, belonging to the omnivorous animal, generally feeding on aquatic plants, but occasionally improving life, eating meat and fish.
Hippos eat watermelon
According to the zoo's hippos staff, this guy can eat 75 kilograms of elephant grass and 10 kilograms of concentrate per day. Therefore, the more you eat, the amount of excretion is naturally amazing. And in the world of hippos, there is no "civilized toilet" rule, often open defecation, and even sometimes "eat while pulling", which is really impossible to look at.
Hippos who are passionate about dry rice
However, this is the normal physiological need of hippos, so there is nothing wrong with itself. But the fish in the Mara River Basin in Africa are very unlucky.
The river flows through Kenya and Tanzania in Africa and is about 395 kilometers long, with a large number of hippos and crocodiles living in it. The dispute between hippos and crocodiles will be discussed later, and here we will talk about the "school of dead fish" that often appear on the Mara River.
The location of the Mara River
It turned out that every year when the rainy season came, the Mara River received a large amount of supplies, and its water would swell. In this case, thousands of river horses in the upper reaches of the river will drift down the river. Originally, hippos defecating this kind of thing is a good thing for the waters, because it is like an "exchange pump" that allows various trace elements to be exchanged within the watershed system.
Jonas Schoelynck, a biologist at the University of Antwerp in Belgium, explains, "Most herbivores return the nutrients they ingest through excretion to the savannah. But hippos are different, they are like a nutrient exchange pump, connecting land and lakes. ”
The material cycle of nature
Because from the determination of the silicon element in the Mara River, after the hippopotamus eats aquatic plants, it will discharge half of the silicon elements in the plants into the Mara River, so that the diatoms can survive.
Such single-celled algae are the basis for the survival of many fish in the watershed. Therefore, hippopotamus defecating in the river originally contributed to the ecological cycle.
But we all know that once something is "too much", it becomes smelly. So as the number of hippos in the Mara River basin continues to increase, so does their feces. In this case, the hippopotamus excretes up to 8.5 tons per day, and after they enter the river, they will continue to consume oxygen in the process of decomposition.
Schools of fish that die of asphyxia due to lack of oxygen
At this time, the fish living in the "huge septic tank" are not only forced to shuttle through the fecal debris of the hippopotamus, but also face the dilemma of no oxygen.
Therefore, after witnessing the bizarre deaths of thousands of fish on the Mara River every year, ecologists in the United States finally found the culprit hippopotamus, and also wrote an article called "The organic matter load produced by the hippopotamus causes oversupply, resulting in downstream hypoxia and fish death", which explains the reason for the mass death of the fish population.
The number of dead fish is staggering
It can be said that this is a very bizarre and strange way to die, and the fish will be choked to death by the "feces" of the hippopotamus. However, in addition to the consumption of oxygen, hippopotamus feces also produce substances such as hydrogen sulfide during the decomposition process, which are also toxic to fish.
Seeing this, many people may say that this is the reason why the river is called "Mara River", after all, this river is full of hippotamus feces, and it is not too much to call the toilet of hippopotamus. So, in addition to the random defecation of hippos in the river, which creatures do harm to fish?
Hippos excreting in the water
Hippos and crocodiles at war
When we introduced the Mara River in the previous article, we mentioned that in addition to hippos in this river, there are crocodiles. Logically, according to our understanding of crocodiles, hippos should be just their plate food, but in fact, we underestimated the hippopotamus.
First of all, the hippopotamus that grazes most of the time does look "soft and cute", but this guy's big mouth and canine teeth are no joke. Its mouth is not only open and closed, but also has a bite force of 127 kg/cm2.
Hippopotamus is not weak in combat
Secondly, hippopotamus has a very strong sense of territory. Other creatures that enter their territory will be intimidated and expelled, and even fishermen who stray into the hippopotamus territory will be attacked, and the grumpy hippopotamus will frantically bump against the boat, overturn it, and then attack it with a big mouth.
In this case, although the Nile crocodile is very strong, it may not be able to take advantage of the struggle with hippos. Because from the difference in size between the two sides, although the Nile crocodile has the advantage in length, its tonnage is far inferior to that of hippopotamus. Adult hippos weigh more than 1300 kilograms, and only large bay crocodiles can fight with them at this level.
Ferocious Nile crocodile
Therefore, crocodiles generally choose small hippos to start, after all, the big ones can't fight, and the small ones can still bully them. But hippos, as social animals, are very fond of getting together, so once crocodiles are caught on the spot when attacking small hippos, they may face a "beating".
And hippos are notoriously thick-skinned, so when hippos and crocodiles are one-on-one, crocodiles tend to face the dilemma of not knowing where to start.
Use "Death Roll" on hippopotamus
For example, South African wildlife photographer Lenatta captured crocodiles being beaten by hippos in Kruger National Park. Even funnier is that the crocodile was actually crossing the river with the zebra head it had just captured, but it frightened the small hippopotamus next to it. So the angry mother hippo flew towards the crocodile and launched an attack.
Crocodiles that have been attacked
Maybe the crocodiles are blinded and don't understand why they can be beaten when they cross the river with their prey. So it had to retreat and avoid it, and eventually returned to the place where a large number of crocodiles gathered with its prey, and was forced to share food with other crocodiles.
In short, the overlap of hippo and crocodile territories is an indisputable fact. Except for the occasional fight, the two creatures maintain the status quo of well water most of the time, and even photographers sometimes take pictures of crocodiles lying on hippos basking in the sun, which seems to be relatively harmonious.
Occasionally bask in the sun together
It is worth mentioning that the size and combat effectiveness of hippos are actually traceable, and even some family genetic components, because scientists have found through research that hippos and whales actually have the same ancestor.
Hippos are the same ancestor as whales
Hippos are of the same lineage as whales
From the biological classification of hippos, we can see some clues, this guy belongs to the mammalian order, whales and hooves. When biologists searched for the ancestors of hippos through DNA sequencing technology, they found that there was a close relationship between this guy and whales.
Taxonomists believe that hippos share the same semi-aquatic ancestor as whales, and diverged from odd-hoofed animals 60 million years ago and began to live in the ocean. It wasn't until 5 million years ago that hippos diverged again and returned to land to become what they are now.
A network of relationships between the two
So don't look at the hippopotamus by that name, but it really has nothing to do with the horses of the strange hoofed order. If you look closely, you will find that some of the characteristics of hippos are indeed very similar to whales.
In short, the hippopotamus can be regarded as a very old animal, although it has a somewhat grumpy temper, but there is no "bad mind" in essence. If the population is controlled within a certain amount, its feces will not cause much harm to the fish in the river.
Hippopotamus habitats are getting smaller and smaller
In fact, when we look back at the causes and consequences of the disaster caused by hippos, we will find that there is actually a human help behind this. Because the habitat of wild hippos has been further compressed over the years under the circumstances of human wanton expansion of territory, the population distribution will be too dense.