By Jerry Kirkhart - originally posted to Flickr as Vole (Microtus), CC BY 2.0, https://commons.wikimedia.org/w/index.p ... d=10888052
This critter is commonly called the California Field Mouse, but it is much larger than a mouse, more the size of a guinea pig.
While guinea pigs are commonly kept as pets, the California vole is not.
The image below taken by Sandos at the English language Wikipedia, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=119899 is that of a guinea pig. Notice the ears are smaller, and look like pig ears.
By Sandos at the English language Wikipedia, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=119899