This article was written by Eva Mitchell, Minneapolis Parks and Recreation Board Naturalist at North Mississippi Regional Park
We learn from a young age that beavers are some of nature’s best engineers, building dams and lodges in bodies of water that sometimes are so effective in changing the flow that they disrupt nearby human activity. So, as Sylvia asks, why do they do it? In short, the answer is that beavers build dams to deepen water where they can build the homes, or “lodges,” that keep them safe.
Beaver lodges are special shelters made from layers of tree branches, leaves, grasses, rocks and mud that can be as large as 40 feet wide and six feet tall. Beaver families, usually comprised of adult parents and any offspring younger than two years old, will share a lodge and continuously renovate it as needed for stronger walls or more space. While the inside living space of the lodge is mostly above water, the inhabitants dig tunnels that act as doorways directly into the water. These tunnels allow them to safely come and go as needed, without alerting nearby predators to their whereabouts. Inside the lodge there can be several different rooms where the beavers will sleep, eat and socialize as a family with particular attention to keeping the youngest members well-fed and warm. These lodges provide year-round protection to beavers, who can survive Minnesota’s cold winters with help from the insulated walls of their home as well as the food they have stockpiled in and near their lodge. While in their shelters beavers are safe from predators such as coyotes, wolves, bears, bobcats and cougars.
Beavers will often engineer dams in lakes, streams and rivers where the water flow can be slowed down, resulting in deeper water and better conditions for building their lodges. Dam construction begins by using their sharp teeth to gnaw down nearby trees; beavers then carry and swim with the large branches, placing them in a deliberate line. This work is typically done as a family unit or “colony,” beavers repeat this step until branches are piled and interlocked, combined with rocks, mud and other debris until an effective dam re-directs water flow and often creates new ponds. To ensure the dam is solid, beavers will respond to the sound of rushing water through any holes and keep packing on materials until there are no longer gaps. In spacious natural environments, beaver dams and ponds positively contribute to the variety and abundance of wildlife while creating rich habitats for plants and animals by keeping water on the landscape. However, when close to human habitation, beaver activity can be detrimental, leading to a significant loss of trees and flooding of nearby public and private property, and roads.
Beaver habitat is widespread across Minnesota and, while numbers once dropped intensely due to over-hunting for pelts, they are now considered to be abundant by the Minnesota Department of Natural Resources. We are lucky enough to have beavers right here in North Mississippi Regional Park, and visitors can even find some evidence of their presence! Stop by the Kroening Interpretive Center and borrow a pair of snowshoes to explore the park, available for free during our normal hours of operation. As with any wildlife, please show respect for any beavers you may encounter… enjoy observing them from afar and do not approach or disturb their home!
As impressive engineers that thrive year-round in every Minnesota county, beavers remain some of our most special neighbors with many exciting adaptations. Join a naturalist for a free Watching Wildlife hike on Saturday, February 22 from 11:30 a.m.-12:30 p.m. to find out how to identify and follow the signs animals leave behind. Plus take a closer look at real artifacts to learn even more about beavers and other local wildlife! Thanks for the question, Sylvia!
Public programs in February – Free for all ages unless noted otherwise
Saturday, 2/1 – Bird Watching: Birding on Snowshoes, 11:30-1 p.m.
Sunday, 2/2 – Family Funday: Groundhog Day Celebration, 1-3 p.m.
Saturday, 2/8 – Nature Art: Colors and Ice, 1:30-2:30 p.m.
Sunday, 2/9 – Nature Tots: Animal Babies, 11:30 a.m.-12:30 p.m., $5, ages 2-6
Sunday, 2/9 & 2/23 – Nature Book Club, 4:30-6 p.m., $2, ages 18+
Tuesday, 2/11 & 2/25 – Phenology Hike Club, 4-5 p.m., ages 16+
Wednesdays 2/12 to 3/18 – Nature Nuts: Nature Play Group, 10:15-11:15 a.m., $24, ages 2-6
Thursday, 2/13 – Homeschool Day: Orienteering, 1-3 p.m., $5, ages 3-13
Friday, 2/14 – Valentine’s Day Fireside Snowshoeing, 7-8:30 p.m., $14, ages 18+
Sunday, 2/16 – Outdoors: Minnesota Owls, 2:30-4 p.m.
Tuesday, 2/19 – Birds of Prey, 9-10:30 a.m., $5, ages 18+
Saturday, 2/22 – Hike: Watching Wildlife, 11:30 a.m.-12:30 p.m.
Saturday, 2/29 – Special Event: Leap Year Day, 1-3 p.m.
Find registration for these programs and more at minneapolisparks.org/nature or call 612-370-4844 for more details. Do you have a question about nature in your own backyard? Then send it our way by emailing northmississippi@minneapolisparks.org and it could appear in a future article. Like us on Facebook to stay in the loop about what is happening at your park.