BY GUEST BLOGGER: Ben Eisinger

Credit: Maine Public

Despite being an island, surrounded by sea on all sides, Deer Isle boasts numerous bodies of freshwater, including Ames Pond and the Lily Pond. When walking or paddling along the shore, you may encounter something special if you spot an odd ‘V’ shape gliding along the surface, a ripple that is distinct from the others along the surface. You might even hear a loud clap sounding eerily like a gunshot, and spot a large splash where once all was relatively calm and still. Looking around the shoreline, your eyes may see oddly-shaped, ‘rounded’ spear points where you’d expect to see the flat surface of a tree stump, left by a saw. You might even find more fallen trees littering the ground than usual, especially in the absence of a recent storm. And finally, out on the water, rising up out of the glassy surface, you may spot a large dome rising up from the middle of the pond. It may look like just a heap of sticks, but that’s actually a beaver lodge, home to a family of North American beavers.

There are only two species of beaver on earth, the Eurasian Beaver and the North American Beaver, with the North American being the slightly larger of the two and can weigh more than 60 lbs. Despite their impressive size, they are only the second-largest member of the rodent species, with the capybara of South America being even larger. While capybaras may win on size, they have a reputation for being rather ‘smooth-brained,’ whereas beavers are known for their smarts. Beavers are well adapted to water, a trait they share with other semi-aquatic rodents such as muskrats, but they are the only rodent to demonstrate an aptitude for construction. Using their teeth, they chew through the bark and wood of trees, leaving cone-shaped stumps behind. They chew a circle along the whole diameter of a tree trunk, rather than going straight through as we humans tend to do with our saws and axes. As beavers near the point at which the tree will fall, they begin to take frequent pauses in their work to listen for sounds of cracking, often inaudible to the human ear. Once the warning cracks are heard, the beaver retreats to wait. Seemingly, they can judge perfectly from the sounds made by the target tree in which direction it will fall, keeping them safe from being crushed underneath the heavy trunk. Would that humans could enjoy a similar sensitivity!

There are many other interesting facts about beavers. You may, logically, be wondering why a rodent, an animal family usually famed for its burrowing capabilities on land, has become an expert semi-aquatic lumberjack and construction worker? The surprising answer is that we aren’t really certain. It was once assumed that the beaver simply never burrowed underground, as the wetlands beavers live in lack firm soil to safely burrow into. However, the discovery of unique, ancient corkscrew-shaped burrows, dubbed “Devil’s Corkscrews,” had in fact been dug by an ancestral beaver cousin, Paleocastor. Fossilized skeletons of Paleocastor show none of the physical characteristics, such as the signature flat-as-a-pancake tail and hand-like forepaws for grabbing twigs, transparent eyelids to see out of while swimming underwater, etc., which appear in its descendants, and it does not appear to have been a terribly proficient swimmer. Ultimately, it appears that environmental changes led to the change in beaver behavior throughout history

Modern-day beavers are perhaps best known for their distinctive homes, called lodges. The design is simple yet effective: a packed mound of mud with a heap of branches on it! There’s a lot of thought going into the design, of course, especially when one compares the lodges of juvenile beavers and those of experienced adults. In winter, all the mud freezes, providing a hard, insulated dome inside which is an ideal ‘burrow’ for a beaver. Rather than dig down, beavers dig ‘up,’ with lodges always having their entrances below the water’s surface. This is because winds and cold air cannot penetrate the surface, which keeps the inside of the lodge an ideal temperature at all times, perfect for raising baby beavers, or kits.

A bit ironically for a semi-aquatic species, beavers cannot stand the sound of running water. It instinctively drives them to build. This peculiar habit drives the construction of beaver dams at rivers and streams, even storm drainage pipes. This has dramatic effects on the landscape in which they live, as the dams serve to trap water and can lead to the expansion, and even creation, of whole ponds! This makes beavers the prestigious holders of the title for most impactful species on their environment second only to humans, but while this behavior can be frustrating for those humans whose real estate values diminish as a result of their yards becoming filled with water and their homes sustaining water damage (true story from this author’s college professor, who worked with a man blighted with this very problem!), others have discovered that this habit can actually be taken advantage of for preservation, conservation, and eco-friendly initiatives. By playing the sound of running water at the desired construction site, beavers in the area move remarkably fast, and a dam will likely materialize at the site in no time. 

A famous example recently occurred in the Czech Republic. The government had been planning a wetlands-restoration project, budgeted at $1.2 million, for seven years, but was stalled by bureaucratic obstacles and land ownership issues. But when a beaver family moved into the area, they had no knowledge of the political dispute they had unknowingly waded into, and simply did as their natural habits demanded. In just two days, these enterprising creatures had built a series of natural dams in the area, saving the government both time and money, and achieving the desired results better than the original project had been projected to achieve. No wonder we have the famous saying: “Busy as a beaver!”

Ben Eisinger is part of the waterfront staff at Osprey’s Echo Sea Kayaking.