Hiking the Border Route Trail near Grand Marais in October 2015, Mike Burville happened upon a makeshift section of trail broken by other hikers. It was a backcountry detour of sorts to steer clear of a new water project.

Freshly felled trees marked the rugged landscape as water began to pool, thanks to the toothy handy work of nature's most industrious civil engineer — castor canadensis, aka the beaver.

"It's pretty rare to see a beaver on land, but I saw one dragging a branch to the main water flow," said Burville, an avid backcountry hiker from Farmington. "I watched for a while, but when he saw me, he bailed into the water and slapped his tail at me."

Roughly 48 hours later, Burville returned and found even more water and the formation of a dam. "He was busy working away," he said.

The largest rodent in North America, the beaver is nothing if not a force of nature, a critter constantly at work and brilliantly adapted for its aquatic environment. With orange teeth, a flat, paddle-shaped tail and an insatiable desire for cutting trees and building dams, beavers are, as one biologist put it, equally fascinating and frustrating. An old saying: A beaver in the right place is an ideal conservationist; a beaver in the wrong place is a nuisance.

Beavers also have an important and unique history unlike any other North American critter, scientists and others say. Indeed, the beaver's luxuriant pelt — long, coarse hairs over a thick, woolly undercoat — lured early trappers and voyageurs to Minnesota and actually led to the exploration and settlement of the state. Several Minnesota counties are named after well-known fur traders while many townships, lakes and creeks are named after the beaver. The famous Kawishiwi River near Ely is said to mean "river full of beaver houses" by the Ojibwe. Historical documents show how mountain men of the 1800s relied on beaver as the Bitcoin of their era. Not only did they rely on the animal's surprisingly delicious meat, they used its hide as currency to buy supplies.

"Beavers are the most important natural resource in our country's history, and I don't think that's well-known or appreciated enough," said Ben Goldfarb, author of the book "Eager: The Surprising, Secret Life of Beavers and Why They Matter."

"Beavers are intimately intertwined with American history and most important historical events before the Civil War were motivated to secure more land to trap beavers. So we have the Fur Trade as this great historic event, and we also have this great ecological event that is still playing out today. How do we balance the enormous good beavers do environmentally with some of the problems they cause?"

Beaver adaptation

John Erb is a state scientist who studies furbearers and wolves. He is with the Minnesota Department of Natural Resources in Grand Rapids. He has given numerous public presentations over the years about beavers and said what fascinates him most is how they adapted and consequently thrived in their wet habitat.

Beavers, he said, have ear and nose valves that shut (and keep water out) as the animals submerge. Their eyes have protective membranes — similar to birds — that act as natural goggles against irritation.

Beavers use their web feet for propulsion, while their tail acts as a rudder and scull. And, of course, beavers have extraordinary teeth — teeth that act like chisels and grow constantly.

"They can cut through a six-inch tree in something like 15 minutes," said Erb. "They've evolved perfectly for an aquatic environment." A single beaver can cut down hundreds of trees each year.

Found in every Minnesota country, beavers are skilled at creating wetland-like pools that increase biodiversity, provide wildlife habitat, improve water quality, and help prevent flooding, Erb said. Conversely, their dam-building can flood roads and valuable farmland, and their penchant for tree-cutting has resulted in the loss of valuable fruit and shade trees. "It all depends on your perspective at a given time," said Erb. "People love having a beaver pond on their property in most cases because they get to see ducks and other wildlife. But if their property gets flooded, attitudes understandably change."

Continued research

Steve Windels is a wildlife biologist at Voyageurs National Park, headquartered in International Falls. He is one of several scientists who have conducted beaver research at the 218,000-acre park. Roughly 50 research papers have been produced since research began there in 1983. Windels said the cumulative research shows Voyageurs might contain the highest density of beavers in the United States.

"They're a keystone species … and their removal can result in a cascade of changes for other species in the system," Windels said.

Indeed, Windels said beaver research at the park suggests that at least 124 bird species, mammals, reptiles and amphibians use "beaver-created wetlands," — or about 38 percent of the park's inhabitants.

"In many ways, American beavers are to Voyageurs as wolves are to Yellowstone National Park, or wildebeest are to the Serengeti," said Windels, adding the densities at Voyageurs are likely similar to those before European settlement dramatically altered the landscape. "Thus, Voyageurs National Park presents a unique window into the past about the dramatic importance of beavers to shaping their environment."

Beaver coexistence

Goldfarb said the federal government in 2017 killed 23,646 "problem" beavers. He said beavers are blamed for far too many problems and would like to see more nonlethal strategies for dealing with so-called nuisance beavers. "If I learned one thing from researching my book, it can be done," he said. "Beavers don't have a lot advocates, but they furnish us with numerous ecosystem services that support a vast menagerie. Do some beavers cause such problems that they need to be dealt with? Yes. But I think we've gone overboard."

Tori J. McCormick is a freelance writer from Prior Lake. Reach him at torimccormick33@gmail.com.