Have you ever heard of the Hoover Dam? It’s a big wall in Nevada, USA, that stops a river and makes a lake. But did you know there’s an even longer dam in Alberta, Canada? It’s so long you can see it from space! And guess what? It was built by beavers, not people!
Beavers are amazing animals that build dams. But why do they do it? You might think they live in the dams, but that’s not true. Beavers actually live in special homes called lodges. So, why do they work so hard to build dams?
Beavers build dams to make ponds. They need ponds because they are great swimmers but not very fast on land. Their back feet are webbed like a duck’s, and their flat tails help them steer in the water. A pond is like a safe swimming pool for them!
When there’s no pond around, beavers build a dam to stop a river and make a pond. This way, they can build their lodge in the middle of the pond, safe from animals like wolves and bears. The water acts like a moat around a castle, keeping them safe.
Beavers are smart! They make secret underwater tunnels to get in and out of their lodges without being seen. If a predator comes close, a beaver will slap its tail on the water to warn others to swim to safety.
Beavers love eating tree bark and leaves. In the fall, they store branches under the water near their lodge. When winter comes and the pond freezes, they can swim to their stash and have a snack without going out in the cold.
So, beavers build dams to create ponds where they can live safely. The ponds help protect them from predators and give them a place to store food. Beavers are truly amazing builders!
Thanks for learning about beavers with me! Remember, there are always more questions to explore. Stay curious and keep discovering new things!
Build Your Own Mini Dam: Gather some small rocks, sticks, and mud from your backyard or a nearby park. Find a small stream or create a shallow water area in a tray. Try building a mini dam just like a beaver! Notice how the water changes when you block it. Does it create a small pond? What happens if you remove some of the sticks or rocks?
Beaver Lodge Craft: Use craft materials like paper cups, clay, and twigs to create your own beaver lodge. Think about how beavers use underwater tunnels to enter their lodges. Can you design a secret entrance for your lodge? Share your creation with a friend or family member and explain how beavers stay safe in their lodges.
Observe and Report: Next time you visit a pond or a stream, take a notebook with you. Look for signs of beaver activity, like gnawed tree trunks or small dams. Write down or draw what you see. If you can’t find any beaver signs, imagine what it would be like if beavers lived there. How would they change the environment?
Sure! Here’s a sanitized version of the transcript:
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(phone ringing) – Hi, it’s Doug. You see this? This is the Hoover Dam in Nevada, USA. A dam is a place where people have walled off part of a river and created a lake behind the wall. Hoover Dam is huge, but it isn’t even the tallest or the longest dam in the world. Check out this one in Alberta, Canada. It’s not very tall, but it’s almost twice as long as the Hoover Dam. In fact, it’s so long that it shows up on satellite images from space. And the most amazing thing of all: this dam wasn’t built with cranes or cement trucks or tractors like most dams; it was made almost entirely by beavers.
Someone named Mateo has a question about beavers and dams. Let’s give Mateo a call now. (phone ringing) – Hi, Matteo. – Hi, Doug. – I have a question for you. Why do beavers build dams? – That’s a great question. This is a beaver dam. Why do beavers build these? Well, at first, I didn’t know the answer to this question either. I thought that a beaver dam must be a house where beavers lived, but it surprised me to find out that beaver dams aren’t where beavers live. They’re not houses at all.
So why do they build them then? I mean, building a dam seems like a lot of work, especially since beavers are so small, and it is a lot of work. For a beaver to build a dam can take weeks, months, or even years to completely finish. And if you think about why it makes sense, it takes so long. First, they need to cut down tall trees, then they drag them all the way to the middle of a river. Then they pile rocks and sticks and plants on top of it to make it taller. So if they’re not going to live in a dam, why do they go through all this trouble? There must be a good reason, right?
Before I say anything more, I’m curious. Why do you think beavers go through all the trouble of building a dam? Now would be a good time to pause the video and discuss. Okay, you ready? Even though dams aren’t beaver houses, scientists have discovered that they have a lot to do with where beavers build their houses. You see, beavers do build houses. Their homes are called lodges. And when a beaver builds a lodge, it needs to find the perfect place. For a beaver, that means a place surrounded by lots of water. Like, if they can find an island in the middle of a pond, that’s perfect. That’s where they’ll build their lodge.
That’s because beavers aren’t very fast on land, but they’re great swimmers. Look closely. You see its back feet? They’re webbed, just like a duck’s. So a beaver can swim really fast, and you notice its flat tail. It turns out that a beaver steers just like the rudder on a boat. So building a lodge in the middle of a pond makes sense. It makes it a lot easier for beavers to escape from danger and swim home if they’re being chased by predators, like wolves or bears. It’s kind of like a moat around a castle. The water helps beavers swim home quickly and keeps dangerous animals away, animals that can’t swim as well.
But what if there’s no pond around? Like, what if the only water nearby is a river? A beaver can’t just build a lodge in the middle of a rushing river. The fast-moving current would just carry their home away. This is where a dam comes in. By building a dam, the beaver blocks the rushing water and turns the river from this to this—a totally calm and peaceful pond. Once they have a pond, there’s no more rushing water or fast-moving current that can carry away their lodge, and they’ll have a safe place to build.
Now, you may be wondering, what about when beavers have to go outside to build dams or collect food? Couldn’t they get attacked by a predator then? But beavers have that figured out too. A beaver dam floods the land, and plants and trees around the river. So now, instead of having to walk everywhere to get wood or food, they can just swim everywhere. It’s kind of like having a water freeway.
And this, in my opinion, is the coolest part. A beaver builds a secret underwater tunnel underneath its lodge so that it can swim in and out without anyone or anything seeing. In fact, when a beaver sees a wolf or other predator coming close, it will start slapping its tail on the water as a warning signal, which tells the other beavers to swim to the secret entrance as fast as they can.
So beavers build dams in order to slow down a rushing river and create a pond where they can live safely. But even that’s not all; they also use these ponds they create for something else. It’s their refrigerator. Beavers love eating bark and leaves off trees. So they spend the entire fall storing tree branches underneath the water of the pond near their secret entrance. When winter comes and the pond freezes on top, they can swim out of their secret tunnels to their stash of sticks whenever they want a snack, then take it back into their cozy lodges. And they can do this without ever having to go out into the snow.
So in summary, beavers build dams to stop the flow of rushing rivers so they can create safe ponds to build their lodges on. Since these lodges are surrounded by water, the beavers who live there are a lot safer from predators. That’s all for this week’s question. Thanks, Matteo, for asking it. Now, we’ll be back with a new question in a couple of weeks, but in the meantime, here are some older questions from the question jar. You can vote on which one you think we should send out next week. You can choose from: how is gold made? How do magicians trick people? Or, how is a rainbow made? So submit your vote when the video is over. I want to hear from all of you watching. There are mysteries all around us. Stay curious and see you next week.
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