Heads in the sand

Some interesting observations of River Otters (Lontra canadensis) this morning (3 October 2018).  This group of three otters was spending some time in the swash zone on a sandy beach:

 

From their postures, it appeared they might be feeding.  Note the young otter on the far left — the nose-up position is one that you often see when otters are eating something.  And check out the mother otter on the far right with her head curved downward.  She appears to be holding something and perhaps chewing on it or manipulating a prey item in some way.

I started to wonder if they might be eating Mole Crabs (Emerita analoga).  So I took a few more pictures.  Watch the young otter in the middle of the photo — you can see it "bulldozing" its head through the sand, perhaps in pursuit of a crab:

 

 

And here's one more photo, with all three otters lined up.  It looks like the younger otter in the foreground might be using its paw to dig at something in the sand:

 

I've read about Sea Otters (Enhydra lutris) eating Mole Crabs, but I haven't seen reference to River Otters doing so.  Perhaps it's an opportunistic behavior?