we're not the only other animals watching beavers!

Beavers in the Stokes Nature Guide to Animal Tracking and Behavior

Nature guides occupy the middle ground between scientific monographs and anecdotal memoirs, and because of that they have an odd freedom. They are not expected to provide evidence for their assertions, neither the statistics of the monograph nor the day-in day-out observations of the memoir. They usually prove that they know what they are about by providing illustrations, either photographs or drawings. This Stokes guide makes a gesture toward displaying the more exacting requirements of the monograph and memoir. At the beginning of its section on beavers it recounts a personal encounter the Stokes' had with a beaver, and in the back of the book it lists scientific monographs and books that it used as its sources. This is a nice touch and adds to the value of the guide, which is not to say that the guide is any more accurate for it.

On a fall evening the Stokes waited on the shore of a small pond across from a beaver lodge, just 25 feet away. They had visited the lodge several times in the summer and saw no signs of beaver activity. Now in the fall, they were extending their vigil beyond an hour to see if a beaver was in the lodge. When it was "almost dark," a beaver came out. "It was huge." First it "swam about in several directions... to be sure everything was in its place." Then it swam toward them causing the Stokes to feel "unnerved" as they "wondered what this huge animal might do." It came as close as three feet, turned and swam away, soon reappearing with a "gray birch in its mouth," which it took to the lodge. The Stokes speculated that it was food for the young beavers in the lodge.

Generally I stay more than 25 feet away from a beaver lodge I am observing. This past Spring I sat behind some small granite boulders about 50 feet from the Beaver Point lodge waiting for the beavers to come out and I feared I was too close. I find that beavers are bolder in the spring so I took the chance, and in due time two beavers came out. One joy of making my stand close to the lodge, and in this case 50 feet was close enough, was that I could hear the beavers mewing before they came out, and also hear the splash and slosh of water as they entered the water in the lodge. My guess is that the Stokes meant to say they were 25 yards from the beaver lodge.

Generally when I see beavers first coming out of a lodge, they are primarily concerned with getting a bite to eat. This would not make them unique among mammals! However, at times they certainly seem to scent me and often come right at me. When they come close to me it is always exciting, but never unnerving in the sense that anything about the beaver arouses any fear. Come to think of it when beavers have swum aggressively near me, they almost always are swimming across my view, not right at me. I suppose this is because they are evaluating my scent wafted toward them by a breeze, and not trying to see me. And what is most prominent when a beaver swims at you, is its nose which is not a very fearful object.

I think the Stokes introductory paragraphs to their chapter on beavers is a bit unfair. They describe a "huge," unnerving animal that comes right at you in a way that leaves you in doubt as to what it will do! Even when an alligator swims toward you, you are prone, I think, to think to yourself: "as long as it stays in the water, I am all right. If it starts climbing out - I'm getting out of here!" And the beaver has no reputation for having any ability to move on land.

The first two points the Stokes make about the beaver's character is its "industriousness," and that "the male and female stay together throughout the year and form a lasting bond." To the casual observer and even to someone like me, both of those characteristics are not apparent. Most of the time when you see beavers in a pond in the early evening they are eating or cruising about - very little industry. Once I saw beavers courting, and they indeed stayed close to each other. But generally you never see a pair of beavers together that you can with confidence say they are mates. Little beavers do more commonly play together.

The Stokes are short on superlatives in describing beavers - no paragraphs about the great engineer here. And they seem to like to share observations that cast doubt on the beavers' engineering ability, e.g. beavers will build a dam on top of a human dam, which does not "add to its efficiency," and "they will also dam up streams that flow into their main pond." Then the Stokes add that since exploded assertion that "the stimulus for building dams seems to come from the sound of rushing water." In my experience, some dams are tight and some always have running water. All dams I have observed have leaked or over-flowed, which excited me a great deal, but didn't seem to faze the beavers. I've observed beavers using the ponds above their main ponds as a place to dive for roots. It makes a great deal of sense to me to flood areas where you want to go root hogging so that you can swim over them and not root around in the mud like a hog. Beavers are not trying to build efficient dams, they are trying to get food.

Well into their chapter the Stokes make the accurate observation about the beavers first eating and grooming when they come out of the lodge, saving work for the cover of darkness (though of course you can often happen upon beavers working in the day light.) However I think they give too human a twist to beaver life by adding, "activities are always centered around the lodge." This is somewhat obvious, but misleading observation. You rarely see beavers on their lodge. In the fall after several below freezing nights they will start packing their lodge with mud. Once, also in the fall, I saw a beaver in Shangri-la Pond sunning itself on top of the lodge around noon. Certainly a beaver always knows where its lodge is, but it doesn't give that impression. I've seen them quite far away from their lodges.

The Stokes make two observations about the beavers' tail slapping: "this has the effect of making other beavers, especially those on shallow water or on land, head for deep water," and "tail slapping is done most by female beavers." In my observation, the tail slapping is done mostly by young beavers, and usually no other beavers pays it any heed. And even when there are more authoritive slaps (and I have no way of knowing the sex of the slapper,) others beavers are not quick to react, even those on land or in shallow water. The meaning of tail slapping evidently is more complex than the Stokes imply. I have found that at night the tail slapping can become unmerciless, repeated so often that it drive me away. In the day the beavers seem more tolerant. To drive humans away they should use the opposite strategy - since we can scarcely see or otherwise sense their presence at night. But I am never sure if my experiences with tail slapping are shaped by variations in my odor and demeanor or if it all depends on the beaver. There is one beaver now in the New Pond which I think is a yearling, who is the principal slapper (when the kits stop doing it.) None of the other beaver react to it in any knee-jerk fashion. But I think this beaver has been gaining more respect. Last time it did it, an adult beaver did look up from its nibbling, and sniff the air. I was up-wind of it and in the usual beaver slow-time, it slipped back into the pond and swam off, away from the lodge into the shallow reaches of the pond.

The Stokes then turn to food and feeding habits. Their list of sources includes a monograph on the summer activity of the beaver and that is probably the inspiration for this observation: "In warmer months, the beavers often collect food and then takes it to a favorite spot to eat it." In my experience, especially in the summer, the beavers individually seem to go all over the place in around the pond, and I never get any sense of a favorite spot, especially do I not get the impression the beavers, as a group, will drag food to one spot, time and again, to eat it. You often find stripped twigs at the end of beaver canals or at the end of dams. But I think these are often the remains of the willow bushes that beavers drag in toward the pond. Willow bush twigs and trunks are so small that it hardly makes sense to put them in the water. With larger trunks with branches, say of maple or ash, it makes sense, that is, there is some advantage to the beaver to put them in the pond and drag them, then or later, to the lodge to feed the young. The only time the beavers seem to have favorite places is in the winter and early spring at certain holes in the ice or under the ice.

Like most everybody else, the Stokes think it is sufficient to identify the trees the beavers like to eat. They list as favorites: aspen, maple, willow, birch, and sweet gum, and amplify aspens to include "any other member of the poplar family, such as cottonwood, balsam, poplar and various willows." In my neck of the woods they like ash and red oak. In another section of this web site I have a section devoted to the beavers and trees, see trees.html. The Stokes also make a great point of saying that the beavers only eat the bark of trees, not the inner wood. However, you will often find them nibbling contentedly on a seemingly stripped tree trunk or branch. So that if you wanted to stake out a beaver pond and be sure to see a beaver eating, one good place to look at is a freshly stripped log. The beavers frequently come back for left overs that might be imperceptible to us.

In this section the Stokes again try to shoot down the woods craft of the beaver, pointing out that the trees they fell often get hung up by other trees. Admittedly it can be very frustrating for a human to see a beautiful maple tree cut by the beaver and left hanging in the branches of some oaks that the beaver will never be able to fell. But while that hanging maple cannot be immediately useful to the beaver, by hastening its death (and all trees eventually die) the beaver lets more sunlight into the pond which can only increase the amount of vegetation available to the beaver in the ensuing spring and summer.

Near the end of their short chapter on beavers, the Stokes make their most important observation as they talk about dam and lodge building in the fall: "but they do not coordinate their actions in any sophisticated way; each one works separately." However, one can quibble with the use of word "sophisticated." In a sense the beaver way of working is more sophisticated than the way humans organize to do work. Beavers seem to have an innately shared sense of what needs to be done and they, in their fashion, get the work done. It maybe mindless but this innate mindlessly probably takes less of a toll on the organism through stress than the human way of regimenting workers into mindlessness. And, by the way, I've seen beavers build lodges and dams in the early summer.

The Stokes guide also includes information on beavers as they discuss the various categories of mammal activity commonly observed in nature. On page 98 they discuss beaver dams and lodges. Two statements give me trouble: "a perfect clue to beaver construction is that the twigs and branches used are totally free of bark because the beavers have chewed it off;" and "when the water level is quite a bit lower than the dam, you can conclude that the dam is not maintained and that the beavers are no longer there." Unless there is a drought! And I have seen unstripped branches used in a beaver dam. They can always get around to debarking them later.

The illustrations used in the book are passable save for the one of a beaver cache. When the beavers store wood for the winter near their lodge, they create one of the most beautiful assemblages to be found in nature. I've never seen a mere branch sticking out of the water. Someone versed in chaos theory should make a study of these caches.

The way the branches become interlaced seems magical to me.

Bob Arnebeck

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