Beaver

Canadians celebrate the beaver as a national symbol on stamps, coins, and emblems; in addition, literally hundreds of Canadian lakes, towns, rivers, and hill ranges bear the name of this interesting rodent.

Beavers are found throughout Canada, north to the mouths of the Mackenzie and Coppermine rivers on the Arctic Ocean. Most common in forested areas, beavers also expand into unforested habitats where there are watercourses bordered by deciduous (broad-leaved) trees or shrubs. Thus, in western Canada, they are found along streams on the dry prairie. Even in the tundra, beavers occasionally colonize shrubby water edges where water is deep enough to allow for food storage and access to the den under the winter ice.

One class was very interested in studying our Canadian beaver. They saw this beaver lodge at Elk Island National Park and learned about the life of a beaver through museum interpreters and artifacts. The lodge is made of wood, mud, grass, twigs, stones, and logs from which the bark has been eaten, piled on the ground with alternating layers of gravel or mud. When finished, the upper surface is plastered with mud, usually dug from the bottom of the pond above the dam, to make it watertight. The lodge is located in the middle of the pond, or attached to the bank of a lake or stream. 

The children built their own beaver lodge, as shown above, using twigs and mud. The hardest part was to create the entrance to the lodge because it needed to be below the water level. The children were also sure that their parents wouldn't know that the hole at the top was the air hole, so they labeled it. There was a lot more respect for the building skills of the beaver after this project was complete.

Evergreen Museum brought this beaver skull to St. Monica school. The children learned some interesting things about beaver teeth:
  1. beaver teeth are orange
  2. their teeth never stop growing
  3. the outside of the teeth is covered with a very strong enamel, but the inside is softer and wears away earlier - this keeps the teeth sharp
Some other interesting facts about the beaver are:
  1. the beaver keeps his fur waterproof by grooming castorium oil throughout the fur; the castor gland is found near the tail. Castorium is also used to mark a beaver's territory.
  2. the beaver will slap his tail hard on the water surface to warn his family of danger; a beaver's slap can be heard for up to 1/2 mile
  3. the beaver has transparent eyelids that protect his eyes when he is underwater; these third eyelids are called nictitating membranes
  4. the beaver can close his nostrils and ears to keep them watertight when he is swimming
  5. the beaver has webbed feet to help him swim
  6. the second toe on the beaver's back feet is split and he uses this claw like a comb
  7. a female beaver is usually about 2 1/2 years old before she has babies and she usually has 2 - 4 babies, called kits, in a litter
  8. beaver raise the water level to surround their lodge with a protective moat, and also create the deep water needed for winter food storage in the northern areas
  9. during the winter, beaver stay warm in their lodges and they do not go hungry because they have an underwater food cache nearby
  10. a beaver colony, usually consists of six or more including parents, yearlings and kits
  11. two-year-olds leave home each spring to find their own territories
  12. small kits have many predators including hawks, owls, bobcat, coyote and dogs - bear, wolves, dogs, lynxes, bobcats, mountain lions, wolverines, bears, otters, red fox, and coyote can also take adults 
  13. beaver almost became extinct in the early 1900's when they were over-trapped; the beaver was trapped for its beautiful fur. The beaver conservation movement began in the late 1930s with the writings and lectures of Grey Owl.
  14. the beaver has to work hard to collect its food and prepare its food cache for winter. If the beaver did not collect food in preparation for winter it might die.
  15. beaver's fat layer helps to streamline it body for easy swimming and insulates it to keep it warm
  16. the beaver's front feet are used to hold wood, to build its lodge, and to plaster mud on dams and lodges
  17. the fur is two layer: short woolly felt and long hollow guard hairs
  18. the beaver can stay under water for 15 to 20 minutes, which means that his lungs are well developed
  19. the beaver uses its tail as a rudder and to store fat in the winter (the tail will enlarge up to three times its normal size). The tail also serves as a "third leg" (kickstand) for support during tree cutting and it is used to slap the water as a warning signal. The beaver does not use its tail to pack mud and build as is often show in cartoons.
  20. the trails that cut trees make as the beaver hauls them to the water are called drags
  21. kits "mew"
  22. a beaver has a special flap behind her teeth to keep its mouth waterproof. This way, it can chew while underwater.
  23. a beaver eats all part of a tree, but the favorite part is the white layer just under the bark
  24. the beaver dam is only built by beavers that need to enlarge the underwater habitat that will be open to them in winter, by creating a pond deep enough that it will not freeze to the bottom
  25. a family of five or six beavers may require half a hectare of dense poplar trees for its winter food supply
  26. beavers build canals to provide easy transportation of food supplies
  27. a beaver takes only one mate, which it keeps for life
  28. beaver are nocturnal animals; while they are seen during the day, much of the beavers' work is accomplished during the evening and night hours

 

In tribes across North America, legend had it that the beaver helped the Great Spirit build the land, make the seas, and fill both well with animals and people: Long, long ago when the Great Waters surged in a blind and shoreless world, the gigantic beaver swam and dove and spoke with the Great Spirit. The two of them brought up all the mud they could carry, digging out the caves and canyons and shaping the mud into hills and dales, making mountains where cataracts plunged and sang. Some tribes believed that thunder was caused by the great beaver slapping his tail.
In prehistoric times, the beaver's ancestor was enormous! The giant beaver (Castoroides ohioensis) was the largest rodent in North America during the ice age (Quaternary - the last 2 million years.) Giant beavers seem to have preferred lakes and ponds bordered by swamps as their habitat, because their remains have been found in ancient swamp deposits.