Expert dam-building beavers provide distinctive entertainment.

In the wildlife watching world, sometimes it’s easy to get sidetracked from your original goal. You may be targeting a certain species when an unexpected one puts on a show of behaviors that demands examination.

Last week, I found myself on a nearby duck lake, trying to document actions from the last incoming flights of migrating puddle ducks. The weather was ideal; a slight breeze rippled the water to reflect the cloud-free, azure sky, and yellow-orange rays from the morning sun lit the cattail backdrop perfectly and sent streaks of deep-hued gold across the water’s surface.

Unfortunately, only three blue-wing teal occupied the area I watched, and those birds were ultra-wary, avoiding me for the entirety of my stay, save for a couple flyovers by a love struck drake chasing a coy hen.

I had only sat for minutes when a deep hiss emitted from the cattails, followed by intensely louder hissing and the sound of water being moved by a large animal.

Seconds after, a pair of medium-sized beavers rounded a cattail point, swimming rapidly and playfully ramming each other. One of the oversized water rodents would slap its leathery tail, dive and just as quickly reappear topside. Then its partner would mimic the behavior.

When the two beavers were both at the surface, they would push their heads together and growl before starting the whole process over. This scenario played itself out for nearly two hours with two more of the toothy beasts joining in, one of which was a giant specimen, clearly at least double the size of the other three.

At first, I figured this to be some type of mating ritual, but that seemed unlikely as beavers typically mate in January and February and have pups after a four-month gestation period. More likely, the beavers were a family unit where the youngsters had reached maturity and were sparring for rights to a territory.

Young beavers stay with their parents for two years after birth and then move on to their own areas. Or, perhaps, they were just exercising themselves after a long winter of partial social distancing that found them cooped up in their lodge.

I’ve photographed plenty of beavers but had no great images of their signature tail slap, a mechanism used to warn others of immediate danger. The tail slap creates a mini-tsunami and reverberating sound waves when the wide, heavy tail smacks down on the water.

The beavers were a little out of good lens range for full-framed shots, but I solved that by mimicking their growls and hisses. Astonishingly, a pair sped near me, continuing their odd act, apparently not caring about my presence.

One of the critters actually padded out of the slough on a heavily used trail only a few feet from me. The beaver cocked its head at me and nonchalantly slid back into the water without tail slapping.

I collected many bytes of beaver action, including some nice tail slap shots. The only animals that didn’t enjoy the show were a pair of geese that had nested atop the largest beaver lodge. The lodge stood four feet high and was constructed of swamp mud, cattails and sticks.

When the birds descended to the water, they were bumped by two of the seemingly battling beavers as they surfaced. After a berating barrage of honking, the geese scrambled back on their nest, temporarily safe from the beavers’ antics.

As most Minnesotans know, beavers are voracious herbivores who dine on cattail roots, lily pads and most often woody plants. A family of beavers can wreak havoc on small trees and will decimate a large number in just a few nights of serious chomping while they build dams or lodges.

Beaver dams can be massive projects. The largest beaver dam in North America occurs in northern Alberta and was discovered in satellite imagery. This enormous construction project measures 2,800 feet long — over a half-mile — which leaves no doubt to beavers’ dam-building drive and acumen.

Blue Earth County’s Indian Lake Park, located at Mankato’s southern border, was home to a group of tree-clearing beavers this spring. The animals had moved in last fall and constructed a main lodge along the east shore of the lake. While the beavers chewed trees intermittently over the winter, they increased their efforts as the snow pack waned, felling myriad trees on the lake’s perimeter.

To prevent more damage to the park, a trapper was called in and three of the incessantly chewing animals were pulled from the park. You can still see beavers at the park. I frequently exercise my dogs there, and on a recent walk, I observed a large, lone beaver chomping cattails on the park’s northern side.

Beavers are normally shy creatures who do most of their moving and feeding after dark. Because of that, they’re certainly not at the top of most folks’ animal “bucket” lists. After my extraordinary encounter with the brazen group of four, I’ll never overlook any opportunity to record their behaviors again.

Mark Morrison is an avid hunter and fisherman who has been a freelance outdoors writer and photographer for more than 20 years. The Mankato resident since 1979 may be contacted at

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