Mississippi Valley Field Naturalists
March 4, 2011
Canada’s Five Cent Animal: Our Beaver, Past & Present
by Cathy Keddy
The Mississippi Valley Field Naturalists’ (MVFN) public lecture series, Biodiversity and Vital Connections for Fauna, Flora, and People, continues March 17 with the fifth presentation, “Canada’s Five Cent Animal: Our Beaver, Past & Present.” You do not need to be an expert to enjoy these lectures—just bring your curiosity or appreciation for wild nature.
The beaver, Castor canadensis, is Canada’s national animal. It is the second largest rodent in the world next to the capybara, another semi-aquatic rodent (native to South America). Trapped during the fur trade, the beaver played a key role in the exploration and settlement of our country. Historically beaver population in North America reached 60 to 90 million. It is hard to believe today that this species experienced a decline and almost became extinct in the early 1900s. In 1849 the beaver appeared on our first pictorial postage stamp (known as the ‘three-penny beaver’). By 1937 the beaver-on-lodge had made its debut on our nickle.
Generally, we take beavers for granted, but we are still in awe of their unusual tails, ability to overcome massive, solid tree trunks, and their dam engineering feats. Beavers have become more a part of our lives than we realize. Phrases such as “works like a beaver,” “busy beaver,” “eager beaver,” and the verb “to beaver,” are part of our everyday language. We are all familiar with the modern manifestation of the beaver, but how, where, and when did it evolve to become this particular animal? What pressures or circumstances led to such morphology and behaviour? What do vertebrate fossils, fossil beaver-cut wood, and other environmental evidence tell us about our beaver’s heritage and its relatives? Dr. Natalia Rybczynski, paleobiologist with the Canadian Museum of Nature and just back from a research exploration in Antarctica, will lead us on a journey from the beaver’s earliest ancestors, via modern evidence uncovered, to the making of this modern-day national animal.
The next time you are asked about our national animal, by those quite unfamiliar with the Canadian beaver, don’t be at a loss for words. Attend Dr. Rybczynski’s presentation “Canada’s Five Cent Animal: Our Beaver, Past & Present” and you will have a rich treasury of incredible stories to draw upon. She will be speaking at MVFN’s next lecture on Thursday, March 17 at 7:30 p.m., Almonte United Church, 106 Elgin St., Almonte. All are welcome ($5 fee for non-members). For more information please contact MVFN’s Program Chair Cathy Keddy at 613-257-3089.
Mississippi Valley Field Naturalists
September 21, 2006
by Sheila Edwards
Michael Runtz brings to life the work of one of nature’s great engineers in the watershed – the Beaver
A large crowd gathered on Thursday the 14th for Mississippi Valley Field Naturalists (MVFN) September lecture. Michael Runtz was the keynote speaker for the first of a series of talks exploring the “Mississippi Valley Watershed”.
One sign of a great educator is when an audience doesn’t realize how much they are learning. In his presentation “Beaver Ponds in the Watershed”, Michael Runtz showed he is one such educator. His enthusiastic delivery style brought to life information based on his astute observations of nature. A well respected naturalist, nature photographer, and author, Runtz captivated his audience with stories about beavers, the topic of his next natural history book. Based on the response Thursday, it should prove as popular as his other Canadian best-sellers such as Wild Wings, Algonquin Seasons and Moose Country .
Runtz showed us how beavers play the role of engineer when it comes to creating nutrient rich ponds, teeming with life. Water levels are raised, new species are attracted, and the forest gradually acquires a pond, marsh, and ribbon of grassland. The habitats thus created by this impressive rodent are vital to the health of our watershed.
As the seasons change, a beaver pond changes as well. In the spring, nutrients will be washed out, enriching the water downstream; frogs will be at their noisiest, many birds will be arriving to nest in the forest and on dead trees standing in the pond; and the beavers will be busy feeding and working on their dams and lodges. Beavers feed on tree bark, the soft layer under the bark, and also herbaceous plants like pond lilies. As fall approaches, the beaver becomes more visible during the day as it works on creating a food pile for the winter and does fall maintenance on its structures; the lodge’s insulation is upgraded by piling more mud on top and the dam must be high enough to ensure the pond does not completely freeze. The lodge’s exits are about 1.5 m below the water’s surface, at a depth which hopefully will remain unfrozen throughout the winter. The beaver swims underwater to the food pile, eating the branches that are weighed down by less edible wood like alder. Beavers keep the lodge’s upper chamber clean for sleeping by eating and defecating in the lower chamber. Like the rabbit, the beaver has a ‘two-pass’ digestive system to maximize the nutritional benefit of its high-roughage diet.
If you are interested in observing beavers, Runtz had some good suggestions. For the paddler, beaver can stay underwater for as long as 15 minutes, so if they startle and dive down, they could be gone a long time. For the XC-skier, if the hole at the top of the lodge is open, and surrounded by frost; the occupants are alive and well. When watching a beaver cutting wood, they may use their tail as a stool by leaning back on it; they will also use either their front teeth or side teeth depending on whether they are eating or cutting respectively.
On Thursday October 19th, MVFN welcomes guest speaker Aquatic Ecologist, Brian Potter (OMNR) who will discuss “Wetland Habitats in the Watershed” (7:30 p.m. Almonte United Church, 106 Elgin Street). For more information on the lecture series please contact Program Chair Joyce Clinton at 613-257-4879/email , or visit our website at www.mvfn.ca . For those interested in an MVFN nature walk, the next one will be hosted and led by Joel Byrne at his property “Big Creek” near Watsons Corners, Sunday October 15th. If interested, and for more information, please contact Mike McPhail at 613-256-7211 or email