Saturday, June 26, 2010

A Slap-happy Beaver

Beavers slap their tails on the water when they are upset about anything they view as a threat. The loud noise may startle an animal and it also warns other beavers about the danger. The Maxwell beaver family is pretty tame and normally it's members don't slap their tails a lot at people to indicate their alarm. The beaver colonies further up Happy Creek are another story. Those beavers don't particularly care for people at close range, and a large adult let me know it last week, swimming back and forth and slapping repeatedly while I sat on the bank nearby and tried to capture the action in photos.

How can you tell when a beaver is going to slap? First off, they swim with their head much higher in the water than usual, as shown in the first photo. After the first slap swimming back and forth is a sure sign of continued agitation. It's really hard to time the actual action because it happens so fast. I got a decent photo of the early part of the slap - the beaver initiates a dive which raises it's tail above the water and produces speed. As the beaver continues the dive the flat tail whacks the water hard.

Unfortunately I wasn't able to get a good picture of the height of the splash. This somewhat blurry frame was the best I could do. The splash is pretty impressive, and the noise carries a long way. Often the beaver surfaces again right away and continues to swim back and forth slapping until the intruder leaves. Other times the beaver simply disappears - either swimming underwater to a burrow or lodge or simply holding it's breath while wedged under some underwater anchor like a log. I once watched a beaver who had slapped and then stayed under a log for over 10 minutes. I could clearly see the beaver remaining still under the submerged log. I left because I really didn't want to see how long a beaver could hold it's breath and I'm sure that beaver agreed with me.

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