Story and Photographs by Joan Herrmann
Whereiwander – perhaps when you hear the word rodent the mammal which may come to mind first might be mouse or rat or even squirrel. Today’s column is about one of my favorite rodents which is one of the largest too. A memorable encounter with one was first hearing then seeing, the flat-tailed rodent (Castor canadensis) known as an American Beaver. I had left home with my dear husband, at about 4:30 a.m., in hopes of seeing a moose. The site was Helldiver Pond within the Moose River Recreational Area. For many years a large bull moose could be seen in the early morning hours eating aquatic vegetation on this pond. I was hoping to be fortunate to see and photograph this long-sought-after magnificent mammal. As I quietly waited with my husband and another couple, on the dock, I scanned the perimeter of the pond. We were all startled by the unexpected SLAP of a beaver’s tail, but at the same time, I had finally sighted the moose, affectionately known as Harold. I had been looking at him for several seconds, but was so awed struck at finally actually seeing a moose; that I couldn’t even speak until the beaver’s warning sound broke the silence.
All rodents are similar in the fact that they must continually chew or gnaw because their two upper and lower incisors never stop growing. Beavers are fascinating mammals that are monogamous, staying together throughout the year, and have only one mating partner, which is unusual for most wild animals. The female beaver of the colony is the dominant member. The colony most often consists of two to occasionally three kits which are born in the spring; the female, the male, and quite often yearlings from the previous year. The demands of building and maintaining the structure of the dam and lodge is accomplished with the assistance of all colony members.
I have learned that the beaver’s body is ideal for both underwater and land maneuvering. Beavers have very dense, soft, waterproof “under fur” that traps air, insulates, and also keeps them buoyant. Their broad scaly tail in addition to sounding alarms; works as a rudder in the water and as a prop, for balancing them on their hind legs, when cutting down a tree or standing. In the summer heat, their tail works as a heat exchanger allowing them to eliminate as much as twenty-five percent of their body heat. Their hind feet are webbed helping them to swim. They have a split toenail which aids in grooming their fur acting like a comb. The split toenail also assists them when they apply waterproofing oil from their oil gland and when they need to remove parasites and other debris from their fur. The forefeet are not webbed and are kept “balled up” against their chest when they swim. The forefeet are able to carry mud and sticks and are also used to dig, handle food, and for grooming. Beavers have an excellent sense of smell and can easily identify their favorite food tree just by its smell.
A beavers’ top and bottom incisor teeth are orange in color and very large and prominent. Both of the beaver’s ears and its nose have seals that keep the water out while they are underwater. Their eyes are also unique as they have a transparent third eyelid that slides across each eye. This eyelid is called a nictitating membrane and can be found in many birds too. Their loose upper lip closes behind its four incisors which allow them to chew underwater without letting debris or water enter their mouth. The tear-shaped body permits for streamlined maneuverability in the water. While swimming only the beaver’s head is above the water. These features also make a beaver less vulnerable to predators. A beaver is able to stay underwater for up to fifteen minutes and may cover a distance of up to a half-mile in that time. Beavers are strict vegetarians eating leaves, twigs, and trees in spring and summer. Among their favorite trees are aspen, alder, birch, maple, and willow. Adult beavers weigh between forty-five to sixty pounds and are fully mature by two to two and half years old.
Their body length is about twenty-five to thirty inches and their tail is most often nine to ten inches in length. In our area, beavers will mate sometime in late January through the month of March. Their kits are born in April and sometimes as late as July. They only have one litter yearly and the gestation time is one hundred to one hundred and ten days. The kits, usually two, are born fully furred, their eyes are open and they weigh about a pound each. They are able to enter the water within a day after their birth. However, it takes about a month for the oil glands to function enough for them to waterproof their fur. While they are still nursing they will also begin gnawing on wood. By the time they are seven to eight pounds, they can leave the lodge and begin exploring with the adults and their older siblings.
Beaver are engineers extraordinaire; they dam up streams that are too shallow to hide them from predators and to make their lodges and routes of travel safe as they move to and from feeding areas. Most active from dusk to dawn a beaver is able to take down a three-inch diameter tree in less than ten minutes and a five-inch tree in about a half-hour. One beaver will fell the tree and the rest of the family will help with the removal of twigs and branches. In climates like ours where the water freezes, caching food begins in the fall. Tree branches of their favorite foods are secured in the mud below the water near their lodge entrance. The caches may be extremely large since a family of seven can consume about one ton of food over the winter.
I hope that this column may have sparked an interest in learning more about these intriguing rodents.
As a Professional Nature Photographer, Naturalist, and Outdoor Educator, Joan Herrmann has been teaching and doing programs for Schools, Garden Clubs, Libraries, and Nature Centers, about 38 years. After moving from the Rochester area in 1995 she began her Photography business, Essence of Nature, and also became a co-owner of The Artworks in Old Forge, New York. As a docent at Munson, Williams, Proctor Arts Institute, in Utica, New York she has been educating children and adults, for nineteen years.
In 2007 she began working with the Black River Outdoor Educational Program (BROEP) and in 2013 and 2014 did a week-long summer program at BROEP in conjunction with Mohawk Valley Community College (MVCC). Using her love of both nature and photography she created a Flora/Fauna outdoor educational program teaching students (ages 6 to 14) the joys of nature and creative photography skills.
Joan’s love of nature has been a lifelong study of Birds, Wildflowers, Mosses, Ferns, Trees, Amphibians, Reptiles, Grasses, Insects, Spiders, Tracks, Scat, and Galls. She has assisted in the cataloging of all trails used by the hiking Coaches and photographed and identified seasonal Flora.
Since October 2016 she has been writing a bimonthly nature column with Adirondack Express Newspaper. In October of 2019, she began a bi-monthly column with My Little Falls Newspaper. You may reach her at email@example.com