why do beavers build dams

Why Do Beavers Build Dams? It’s in Their Instincts!

Do you know what dams are? Dams are built with the purpose of retaining water from a source for various uses. It is made of massive iron structures, concrete, and other materials. To generate electricity, create artificial lakes, control the flow of water, etcetera, are the many uses of dams. Funny enough, this concept of restraining water to accomplish those objectives are somehow mimicking a beaver. The only difference is the size or the ‘dam’ humans and beavers make. So why do beavers build dams or burrows in most technical terms appropriate?

But the purpose beavers have is not exactly the same as ours. They are not generating electricity for their homes certainly so, why do they do it at all? Let’s figure out what is happening there on the surface and under the water. Those branches, rocks, and mud can tell us about beavers. In this article, we will discuss the strange nature of beavers.

How beavers build dams?

Before we go to the question of why do beavers build dams, let’s discuss how do they build it. Beavers are notorious for building these structures in ponds, lakes, rivers, and other sources of water. Instinctively, they would build a dam or burrows as a home for their families. This dam also serves as a reservoir for food to sustain them during winter.

  1. They start by searching for tree branches, bushes, rocks, boulders, and mud as building materials for the dam.
  2. Then they would build the structure going across the body of water or in the banks. It is properly called burrows instead of dams and has at least two entrances for them to get in.

The amount of material they can accumulate can be mind-bending. Sometimes it can cause problems for other animals and humans if they also depend on the water from this source. Beavers are also very capable workers and do not stop when things do not go as expected.

A rise in water levels because of rain, change of current, or anything that can damage the structure they built. But these rodents would deal with these challenges to guarantee a home good enough to handle the colder weather. They most probably start building before cold weather arrives.

How large beaver dams can be?

The beavers are amazing builders. They are considered the “civil engineers” of the animal kingdom. They also share this title with ants and many other animals that build underground nests. Since we have established why beavers do build dams, we need to also ask how large beaver dams can be.

First up, they usually do not go that big. They try to find a balance between a deep, tranquil water source that does not have a strong current or is prone to flooding. Shallow rivers and streams meet these criteria.

When they find a place that does not change that much, like a lake, their building starts. They will go ahead building burrows, which are unlike dams, do not stop the water. Burrows are usually built at the banks of these water sources.

As mentioned earlier, beavers don’t build big dams. But there is an exception, which includes the single largest beaver dam the world has ever seen. This massive structure built by beavers has a span of around 2800 feet long. It is so massive you can even see it from space! This monumental structure is inside the Wood Buffalo National Park in Alberta, Canada. Some sources say it took at least 30 years to arrive at this point. It was pretty impressive where it can be admired from thousands of miles away with a satellite.

Beavers are also conservative if we talk about height. Around about 5 feet is good enough for them. Although, they don’t stop to create bigger and taller ones that can even go up to 10 feet in height.

Why do beavers build dams and not live on land?

You are probably curious why beavers would build dams over water sources and not on lands. Knowing that they gather branches and rocks from the land, why would they not go ahead and just build their homes there?

Beavers are certainly amphibious creatures, which means they make their life’s activities on water and on land. But when choosing the place where to live, living over water is their preferred choice. Why though? It is mainly because of predators. Beavers are not that fast on land as they are in the water. It is not like they would not adventure themselves on the land to find their supplies. Giving birth and caring for their offspring, and for themselves as well are mostly the reasons.

In cold environments, they would save all the food and supplies they need to endure the winter. They would dig in the bottom of ponds they create with the dams. When the winter arrives, they just go out of the dam underwater. That’s where they take their snacks from, in the massive refrigerator they created.


Clearly, we can see that beavers are some amazing animals that we can learn from. They are hard-working and takes the trouble of building massive structures just to ensure a safe home for their herd. So that answers the question, why do beavers build dams or burrows.

Dams are built in shallow water sources to get a pond safe enough to store their food supplies. Like hamsters, they prepare ahead and keep stocks that will sustain them during winter.

Being in the water is the perfect place for them to live in. That’s why they take all the trouble to keep themselves safe, as beavers are not great at running from predators on land.

On our next article, we’ll introduce another hardworking creature in the animal kingdom.

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