Hey Patty. The beavers use that "tail slap " as a warning to the others in their clan, that humans are around the Lodge. Beaver Lodges all ways have 2 different underwater entrances so they can go in and out while submerged. Beaver teeth grow continually during their life, so they have to keep working at cutting down trees and branches, which they use to build their Lodges and water control dams.
The Beaver was so important to Canada's primary economy that it is featured on our Five Cent coin. Beaver pelts were worth a fortune in our early days as a trading item. The Courier Du Bois ( the woods runners ) travelled great distances to the North West from Montreal, to trade with the Natives for furs. Big 40 foot cargo canoes, with 6 or 8 paddlers made the long river and lake journeys to meet at western trading posts. The furs were exchanged for European trading goods, like iron tools, blankets, pots and the like. A bale of Beaver pelts was at one time, a type of currency item. The pelts were shipped to Europe, where they were made into hats, coats and lady's muffs. JIM.