A long time ago, many beavers lived in Scotland.
But their fur became very popular for making coats, and people thought beavers tasted delicious.
They hunted all the beavers until they were gone.
That happened over four hundred years ago.
Today scientists are worried that the beavers have not returned.
So they have decided to learn more about the beaver's habitat.
Habitat means the natural place where an animal lives.
If scientists know more about how beavers live, they can encourage beavers to return to Scotland.
When a beaver turns three years old, it leaves its family and swims downriver to build a new home.
A beaver's home is called a lodge.
It looks like a big pile of sticks, but it is actually a carefully designed house.
Beaver lodges are made of small tree branches and mud that are piled in the shape of an upside down bowl.
Most lodges are two to three meters high, three to six meters wide, and full of tunnels.
Some tunnels lead to the rooms inside where the beavers live.
Other tunnels store food.
There are also secret tunnels that confuse predators—so hungry animals don't make beaver soup for dinner!
Beavers build their lodges in streams, and the entrance is always underwater so that it is hard to find.
For a long time, scientists were confused about the size of a beaver lodge.
Most beaver families have a mom, a dad, and one to four babies, which are called kits.
Why did they need so much room?
After watching beavers for a long time, scientists found two answers to their question.
First, beavers build big homes because they need thick walls to keep out predators.
Second, beavers need a place to store their food.
Since beavers do not hibernate, they need a warm, safe place and lots of food when the weather gets cold.
In the north many lakes turn to ice in the winter.
The ice often traps beavers inside their lodge, so beavers need to store enough food to make sure they don't get hungry.
Beavers will often build their lodge with young trees on the inside so they can eat the bark during winter.
Beavers love to eat bark, especially from aspen and cottonwood trees.
Beavers also like to eat clover and raspberry bushes, but their favorite food is water lilies.
Many people think beavers eat fish, but this is not true.
The best way to find a beaver habitat is to look for a lot of water.
Beavers always build a dam near their lodge.
It makes the stream slow down and creates a pond.
This way the lodge is surrounded by water, making it look like a tiny island.
After watching beavers for a long time, scientists learned that beavers live for about ten years.
Once two beavers decide to make a family, they never leave each other.
Beavers somehow always know when there are too many beavers living on their river.
They have the right-sized family to keep the river from getting crowded.
Now that the scientists know what beavers like to eat, where they like to live,
and how they build their homes, they are working to make Scotland a place that beavers can call home.