Story and photos by Joan Herrmann
Where I walk… today is not far from home to a beaver meadow. Beavers (Castor canadensis) are fascinating rodents, and I remember a memorable encounter with one while I was out looking for a moose at Helldiver Pond to see and photograph. This pond is in the Moose River Recreation Area, and my husband and I had left home at 4:30 a.m. since the moose were early birds and the drive was long. While we and another couple waited quietly on the dock, I scanned the edge of the pond with my camera. We were all startled by the unexpected SWAP of a beaver’s tail, and it was at that very moment that I finally caught sight of the moose named Harold. I had been looking at him for several seconds, but was so awestruck after more than thirty years of looking and searching for a moose that I couldn’t even make a sound. The beaver’s tail flicking broke the silence and I pointed across the pond at the moose. Then we all got photos from Harold.
All rodents are similar in that they must constantly chew or gnaw, as their upper and lower incisors never stop growing. Beavers are unique mammals that are monogamous, staying together year-round and having only one mating partner; this is unusual for most wild animals. The female beaver of the colony is the dominant member. The colony usually consists of two, sometimes three young born in the spring: the female, the male, and often yearlings from the previous year. The construction and maintenance of the dam and burrow structure is accomplished with the help of all members of the colony.
The beaver’s body is ideal for locomotion underwater and on land. Beavers have a very dense, soft, waterproof “undercoat” that traps air, provides insulation, and also gives them buoyancy. In addition to sounding the alarm, their broad, scaly tail acts as a rudder in the water and a support to help them balance when felling a tree or standing on their hind legs. In the heat of summer, their tail acts as a heat exchanger, allowing them to lose up to 25 percent of their body heat. Their hind feet are webbed, which helps them swim. They also have a split toenail, which helps them groom by acting like a comb. The split toenail also helps them when they apply waterproof oil from their sebaceous gland and when they need to remove parasites and other debris from their coat. Their front feet are not webbed and are “balled” against their chest when swimming. The front feet can carry mud and sticks and are also used for digging, feeding, and grooming. Beavers have an excellent sense of smell and can identify their favorite food tree simply by smelling it. A beaver’s upper and lower incisors are orange in color and are very large and conspicuous. Both the beaver’s ears and nose have seals that keep water out while they are underwater. Their eyes are also unique in that they have a transparent third eyelid that slides over each eye. This eyelid is called the nictitating membrane and is also found in many birds. Their loose upper lip closes four incisors behind it that allow them to chew underwater without fragments or water entering their mouths. The beaver’s teardrop-shaped body allows it to have streamlined maneuverability in the water. When swimming, only the beaver’s head is above the water. These features also make a beaver less vulnerable to predators. A beaver can stay underwater for up to fifteen minutes and travel a distance of up to half a mile in that time.
Beavers are strict vegetarians and feed on leaves, twigs and trees during the spring and summer. Their favorite trees include aspen, birch, maple and willow. Adult beavers weigh between 20 and 30 pounds and are fully grown at two to two and a half years of age. Their body length is about 2 to 3 feet, and their tail is usually 9 to 10 inches long. In our area, beavers mate sometime between late January and March. Their young are born in April and sometimes as late as July. They have only one litter per year and the gestation period is one hundred to one hundred and ten days. The young, usually two, are born with full fur, their eyes open, and they weigh about a pound each. They can enter the water within a day of their birth. However, it takes about a month for the sebaceous glands to function sufficiently to make their fur waterproof. While they are still nursing, they also begin gnawing on wood. When they weigh seven to eight pounds, they can leave the den and explore with the adults and their older siblings.
Beavers are extraordinary engineers; they dam streams too shallow to hide from predators and to secure their lodgers and their migratory route as they move to and from feeding grounds. Beavers are most active from dusk to dawn and can fell a three-inch diameter tree in less than ten minutes and a five-inch diameter tree in about half an hour. One beaver fells the tree and the rest of the family helps remove twigs and branches. In climates like ours where the water freezes, food stores are created in the fall. Branches of their favorite foods are secured in the mud beneath the water near the entrance to the burrow. The stores can be extremely large, as a family of seven can consume about a ton of food during the winter.
I hope you found this column interesting and that you may have gained some new knowledge about these amazing rodents. I hope to see you too… wherever you wander.
Joan Herrmann has been teaching as a professional nature photographer, naturalist, and outdoor educator for about 38 years, conducting programs for schools, garden clubs, libraries, and nature centers. After moving from the Rochester area in 1995, she started her photography business, Essence of Nature, and became co-owner of The Artworks in Old Forge, New York. As an instructor at the Munson, Williams, Proctor Arts Institute in Utica, New York, she has taught children and adults for nineteen years.
In 2007, she began working with the Black River Outdoor Educational Program (BROEP). In 2013 and 2014, she participated in a week-long summer program at BROEP in conjunction with Mohawk Valley Community College (MVCC).
She used her love of nature and photography to develop an educational outdoor flora and fauna program that teaches students (ages 6 to 14) the joy of nature and creative photography skills.
Joan’s love of nature has led her lifelong study of birds, wildflowers, mosses, ferns, trees, amphibians, reptiles, grasses, insects, spiders, tracks, scat and galls. She has helped catalog all the trails used by the trail coaches and photographed and identified seasonal flora.
She has written a bimonthly nature column for the Adirondack Express newspaper since October 2016. She began a bimonthly column for the My Little Falls newspaper in October 2019. You can reach her at [email protected].