In 1997, a U.S. official wrote to the owner of a territory saying: The government's environmental protection department noticed that you recently built two wood fragment at the outlet of your pond, without the authorization of the government and without the permission of the corresponding department. We believe that such dikes are very dangerous and that if they are not dismantled within a few days, they will be punished by law.
Soon, the owner of the territory wrote back: This embankment was made by a few beavers, we did not pay them, and they did not ask for my consent, but I think that if you call their great engineering pieces of wood, you may have hurt their feelings a lot.
After receiving a reply from the owner of the territory, the authorities immediately revoked the warning and did not prevent the beaver from continuing to build the embankment.
<h1 class="pgc-h-arrow-right" > beaver's dyke</h1>
Beavers belong to the rodent family Beaver family and are the only genus of the beaver family that has survived to this day. There are two species of beavers today, one is the American beaver and the other is the Eurasian beaver, but either of them, they will build dikes, as if the construction of dikes has been engraved in their genes.
Branches are the main material for beavers to build dikes, and they use their sharp front teeth to bite the trees off, then divide them into small sections and bring them back into the river. It is worth noting that beavers are more inclined to branches about 10 centimeters in diameter, and even if they have the ability to bite off larger trees, they will only carry branches with a diameter of about 10 centimeters to the place where the dam is built.
Many people think that beavers just drag wood into the water and then naturally form a. But in fact, the embankments built by beavers are very elaborate.
They will first use thicker branches to lay on the place where the embankment is built, and then use small branches to stagger on top of it, and the side with more branches forked towards the downstream of the river, so that the multi-forked branches can support the dam body from being washed away by the current.
After the construction of branches, the beaver will dive into the water, fill the gaps with sediment and small stones, etc., making it difficult for the water to pass through the embankment, and playing a role in intercepting the water source and raising the water level.
<h1 class="pgc-h-arrow-right" > why should beavers dam? </h1>
The main purpose of our is to regulate water resources, intercept flood peaks, and generate power, that is, humans build levees to prevent natural disasters and produce clean energy at the same time.
But the purpose of damming beavers is obviously not to benefit human beings, they have been building dams since hundreds of thousands of years ago, the purpose is actually to ensure the safety of their nests.
Beavers have no ability to protect themselves, there are many natural enemies in nature, and if they do not have the ability to save their lives, they must have been eliminated by natural selection in evolution.
To avoid predators, beavers usually build their nest entrances below the water and place their nests by the river or in the water.
The beaver's nest is 1.5 to 3.0 meters high, and the diameter of the bottom of the nest house is about 2.5 meters, which is very spacious. In order to avoid predators, the perimeter of the nest is also built with wood and covered with a thick layer of mud, which not only protects their nest from being discovered by other creatures, but also makes the inside of the nest warm in winter and cool in summer.
Beavers build dikes because the river has seasonal variations, and if the water level of the river drops, the entrance to their nest will be exposed, so they will build a dam to intercept the water source and raise the water level.
Although they are built for their own sake, the beavers build that are vital to nature.
We know that wetlands and ponds are very important for aquatic life, not only amphibians and fish can spawn in the water, but even young trout and salmon will be raised in the pond, and many birds will prey here.
When the beaver builds the embankment, it will raise the water level and also expand the wetland area upstream of the embankment, expanding the living space for these creatures. The study found that after the introduction of beavers in the Pacific Northwest, the survival rate of local rainbow trout juveniles increased by 52%.
In addition, the embankments built by beavers can also store water to retain water. In the past, the Suxi River in the United States would hardly flow in July and August, but after the beaver built the embankment, the water flow here can be continuously flowed throughout the year, because the beaver's embankment can store water during the flood period and expand the area of ponds and water flows; in the dry season, the area of ponds or water flows will shrink, and these excess water will rush to the downstream area.
In other words, beavers are actually a dominant species, and the more they live in the local area, the more profitable other local species will be. It's just that beavers also have their own sad side, they can't accurately judge the direction of the tree's fall when they nibble at the tree, so they are smashed to death by the fallen tree.
Two ecologists once discovered that the months of August and November of each year are always the peak of beaver homicides, and found that they were so fond of building dikes during this time that they were often killed by bitten trees.
Perhaps the beaver never imagined when it evolved that its biggest natural enemy was not a carnivore, but was killed by a bitten tree.