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Tuesday, April 2, 2013

Deep impressions

I had to go out onto the tidal flats in Bodega Harbor this morning to check on a research project, and noticed these tracks along the edge of the marsh:

Here's a closer view of one set that made a very deep impression in the sand:

Do you have a guess yet about the animal responsible for these tracks?

The next image has a pencil for scale.  (My pencil is ~ 5.5 inches or 14 cm long.)

Note that both front and hind tracks are visible.  The front tracks are smaller than the hind tracks.  Consistently, the animal placed one hind foot in the same place as one front foot (see center track), so the track pattern looks like three tracks at first, but observe closely and you'll see all four prints.

There are five toes on both the front and hind feet.  The hind feet are especially wide and appear webbed.  Although these are nice impressions in very soft sand, you can tell that the pads on the bottom of the feet aren't well developed (they don't really show up in the tracks).

Do you have a guess now?  (Mine is below the next photo.)

My best guess is River Otter (Lutra canadensis).  River Otters are occasionally seen in different places around Bodega Harbor.  I don't have a great local photo yet, but here's an older one from the Gaffney Point salt marsh.  We were lucky to see this individual crossing the marsh during a botany class in early June 2010.

I first wrote about River Otters after we encountered a couple along the Mendocino Coast last summer.  You can see those photos and learn more about them here.


Amy said...

I have seen river otters frequently around the outflow point near Campbells cove in years past! I asked a colleague here who is pretty good at tracks and she thinks river otter too based on the pattern.

Sarah said...

I have seen river otters near bodega bay several times, twice near goat rock and once near Campbells cove. So they're around.

My favorite sighting of river otters was in Gualala River (further north then us by a bit) I was on the far shore and saw parents and cubs frolicking near the river mouth.

such lovely slippery creatures