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Monday, August 20, 2012

Sleek and streamlined

Early morning field work began with a beautiful fog bank off the Mendocino coast.

The calm ocean conditions may have encouraged the following animals to spend some time along the outer shore.

We were very lucky to see and photograph a couple of River Otters (Lontra canadensis).  Although many people think of River Otters in freshwater lakes and ponds, they also frequent marine shorelines.  On Bodega Head, they have been observed on the outer coast, but more often near Campbell Cove or in Bodega Harbor.

Note the sleek, light brown fur, rounded ears, and especially the long, tapered tail (see below).  The tail is approximately 1/3 of the entire body length and provides stability while swimming.  (In contrast, sea otters have relatively short tails.)

Here's another view of the base of the tail and the hips.  The otters were swimming in a surge channel with Bull Kelp (Nereocystis luetkeana).

The fur color is noticeably paler on the sides of the head and neck.

Note the streamlined profile.  River Otters may use their limbs for swimming, or a "body and tail dorsoventral undulation" (wave-like motion from top to bottom). 

One more observation:  We were alerted to the presence of these otters by a pipping sound.  I heard it and thought to myself, that's not quite right for a bird.  I looked up to see the otters sliding off a rock slope into the water.  Larivière and Walton (1998) state that "North American River Otters also may use a bird-like chirp for communication over longer distances..."

1 comment:

Anonymous said...

lovely otters - i am jealous !!! c