Wild About Utah: Beaver Tail Slap

Oct 16, 2020

A beaver swims in the water.
Credit NPS J. Schmidt

When I first saw a beaver in Cache Valley I thought I'd seen an alligator. I was sitting in the front of a canoe when a large head shot past the bow followed by a black tail that flew into the air and came down on the water with a resounding slap.

 

 

"What was that?" I asked.

 

"I don't know," my friend answered.

 

"I think it was an alligator," I said.

By then the creature had disappeared and we paddled on.

I found out later that tail slapping is a common beaver behavior. It's a warning shot before the beaver dives for cover.

 

Intrigued, I set out to learn more. It came as a surprise to me to find out that when a beaver builds a dam, it is actually building a home. Inside a sturdy wall of sticks, rocks and mud, the beavers build a living space above the water line. It's dry and it's safe because it can only be entered by swimming through underwater tunnels. Not a problem for a beaver who can swim underwater for as long as 15 minutes.

When the surface of the pond freezes over, the females will give birth. It's an extended family life-- an adult pair, the yearlings, and the new kits. When winter is long, and with so many mouths to feed, the beavers have perfected their food storage. Hauling their favorite food, aspen, back to the lodge, they jam it into the muddy bottom of the pond. There it stays fresh and crisp like any refrigerated food, until it's needed.

When fur trappers arrived in Northern Utah in the 1800's, European hat makers had discovered that felted beaver wool made the very best hats. Bear Lake became a hot spot. The historical marker just north of Garden City tells us: Donald MacKenzie, Jim Bridger, and a host of famous beaver hunters operated here. Two major summer frolics and trade fairs brought plenty of excitement to Bear Lake in 1827 and 1828.

 

Trappers were harvesting up to 500lbs a year. But by 1840, the beavers had become almost extinct. European fashion in hats moved on to silk-- a good thing for the hat makers as well because the mercury used in the felting of beaver wool caused all kinds of neurological disorders. It's no joke the Hatter in Alice in Wonderland is mad.

 

Back in northern Utah, the beaver population slowly rebuilt, but the human population also grew and conflicts arose. Recently a farmer in Benson became irate when beavers began to redirect the flow of water through his irrigation canals.

 

Mary holds a beaver while it receives a beaver.
Credit Becky Yeager

It's the job of the Utah Division of Wildlife Resources to live trap and relocate these beavers. I was luckyto be allowed into the loop at this point.

 

When I picked up one of the smaller beavers, I could feel its heart going a mile a minute under my fingers. But it settled down as I sat in a chair holding it against my chest while it got a quick physical checkup.

Holding the beaver close, I had a good look at the nibble fingers on its front feet, the webbing on its back feet that can paddle along at 6mph, and the marvelous flat tail, a good rudder for swimming, a prop for standing on land, and perfect for slapping the water's surface.

Take my word for it, once you've seen this slap up close, you won't forget it.