Mountain Beaver

Oscar the Grouch is alive and well and living in western Washington.

Though seldom seen, this scrappy rodent has been around for over 60 million years.  In fact its lineage is so old it is considered by many taxonomists to be a living fossil.

In spite of being very common throughout western Washington, this animal is so cryptic that it is almost never seen, even by experienced outdoorsmen.

It’s as if nature took a prairie dog, gave it the appetite of a beaver, and endowed it with the climbing skill of a squirrel.
Much like a prairie dog, mountain beaver build extensive subterranean tunnel systems.  Some extending as deep as 10 feet below the surface.

Mature mountain beavers are built stocky and weigh between two and three pounds.  They average about a foot in length and have short fur that ranges from reddish-brown to almost black covering their bodies.  They have a very short stubby tail and powerful forelimbs with sharp claws for burrowing and climbing trees.

These animals are solitary and highly territorial.  Having almost nothing to do with each other except in early spring to mate.  Courtship is anything but romantic.  Minutes after the deed is done the couple go their separate ways without looking back.

Females give birth to two to three young each year and will nurse and raise them alone. Young are born about 29 days after conception and take two years to mature.  They have a lifespan of about 6 years in the wild.

Mountain beaver are so named, not because of any relationship to beavers but because of their diet.  They are actually descended from a common ancestor of squirrels.They have a biological need to consume large amounts of water, as much as two thirds of their body weight every day.  This need for water makes stream banks, ravines and marshy areas prime habitat for them.

They feed on both deciduous and evergreen trees, salal, ferns, and just about anything else green including nettles and rhododendrons.  They are good tree climbers and will chew through branches and saplings up to an inch thick.

Mountain beaver are seldom a problem for homeowners. However, it only takes one or two animals per acre to do significant  damage in a Christmas tree farm, nurserie, or replanted forest land.

As if being a living fossil weren’t enough, mountain beaver have the dubious distinction of being the exclusive hosts of the worlds largest fleas.  Unlike their miniscule kin found on cats and dogs these fleas average 1/4 inch in length. 

Maybe this explains the mountain beavers grumpy disposition.■

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