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Monday, January 20, 2014

Bounding


A nice set of tracks in the Bodega Dunes.  Each footprint was very small — I didn't measure at the time, but I'd estimate less than 1 cm long. 

Note that the prints occur in sets of four with gaps in between (follow them diagonally from the lower left corner to the upper right corner of the picture).  This pattern indicates that the animal was bounding across the sand, rather than walking.

Here's a closer view of two sets of tracks (below).  Although subtle, you should be able to see that in each set, two prints are slightly smaller than the other two.  Which ones are smaller the two in front that are side-by-side, or the two in back that are one-in-front-of-the-other (a bit offset)?


It's the two in back that are one-in-front-of-the-other that are smaller — and these are the front feet.  When bounding, the animal planted its front feet first, and then placed its hind feet ahead of the front feet.

The individual toes are visible in the picture below (there should be five toes, but they don't always register in the sand).


You can probably tell that this is a small mammal.  I'm guessing it's either a mouse or a vole.  I haven't learned to tell their tracks apart yet, but based on the bounding behavior, I'm leaning towards mouse (Peromyscus sp.).  What do you think?

2 comments:

Anonymous said...

Do you think the bounding mouse was speeding up? Starting at the bottom of the photo, it looks like sets 1 &
2, and 2 & 3, are more closely spaced than the later sets (3 & 4, and 4 & 5)? If so, it is fun to think about why the mouse was speeding up. Was it nervous about being out in the open? Or was it excited about some seeds that awaited ahead? -- ES

Amy said...

Hey Jackie,

I have a friend who is excellent with tracks (Leslie Bliss-Ketchum) and she suggests a good sized (adult) deer mouse.

awww...
Amy