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  • Kate Tobie

Beaver Dams

By Kate Tobie

Image credit is Tom Smylie, U.S. Fish and Wildlife Service.

Special to the Enterprise

What did the beaver say to the tree? “It’s been nice gnawing you.”

Beavers are known for being the largest rodents in North America and the second largest rodent around the world. Their habitats vary from streams, marshes, rivers, ponds and lakes. They can grow up to 4 feet and can weigh as much as 110 pounds. Beavers have a stocky build, large flat scaly tail, webbed feet, and large incisor teeth. These physical features are very important as they are also known for building dams and lodges.

Beavers can construct dams across a stream up to 2 meters long and less than 15 meters wide to hold back the stream of water. Across the dam they build lodges in a dome like shape, these can be up to 2 meters tall and 12 meters wide. These lodges have an underwater entrance and a living space above the water line. It provides great insulation as the walls are one-third of a meter thick (check out the image above). In between the dam and lodge a deep water pond is formed that allows beavers a safe access to food supply away from predators. You can find beavers building and gathering food for winter in the summer and fall.

Because beavers can alter their habitat by building dams they can control the biodiversity in the area making them Ecosystem Engineers. Ecosystem Engineers create smaller habitats for other animals in the area and provide accessible food. For example, insects can live on the lodges increasing their population, in turn they are the food source for salmon. Other animals like small rodents and birds can also live on or near the dams and lodges. Ecosystem Engineers are very important, without them biodiversity would decrease and limit the access to resources. Just like our busy beavers, this week’s campers at Extreme Engineering were challenged to work in teams to solve a variety of challenges.

Explorit's coming events:

• Explorit will be CLOSED to the public August 19-September 1 for the installation of our next exhibit.

• Last day to visit our exhibit “Explorit Rocks!” and explore rocks, fossils, minerals, and crystals is Friday, August 18. Open to the public on Fridays from 1-4pm, Saturdays and Sundays from 10am-2pm. Admission is $5 per person. Explorit Members, ASTC, and those age 2 and under free.

• Now is a great time to donate and help Explorit continue to educate and inspire the scientists of tomorrow:

• A Membership to Explorit grants the recipient free visits to Explorit’s regular public hours, discounts on events, summer camps and workshops, and gives you ASTC benefits to visit other museums throughout the world. To purchase or for more information visit or call Explorit at 530-756-0191.

• Now booking school programs for the ’23-’24 school year. For more information, please visit To reserve call (530) 756-0191.

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