Rodent ID help required, SE Arizona

Hi all.

I’ve just returned from two weeks in Arizona where I saw a number of Peromyscus type mice. I would appreciate any thoughts that may help me identify them down to species level. I understand that the photos may not show the detail that is necessary for a confident ID but any opinions are welcome. I’ve also included any other information I feel may help.

The first mouse was photographed in a sandy wash on the Box Canyon road at the foot of Madera Canyon. I’ve included a picture of the habitat in case this helps. The animal had a body length of approximately 7cm while the tail was about 10cm.



The next rodent was trapped near a dam in South East Arizona very close to the New Mexico border. The town of Rodeo is the nearest settlement.

I only have one half decent photo of this mouse. It had a bi-coloured tail and white belly. Body length was approximately 10cm, tail was 8cm. Note the orange lower sides. Any thoughts?


Thanks for any help. More mice to follow…

  1. Author
    Mike Richardson 10 years ago

    Please click on the photo for full image. Hopefully I’ll get it right on my next post!

  2. vdinets 10 years ago

    OK, if you got the measurements for the first one right, I’d call it Peromyscus eremicus. IDing mice in the Southwest always starts with proving it’s not P. maniculatus. In this case, it looks similar, but the tail seems almost naked, and you say it was longer than h&b; both features are indicative of P. eremicus.
    P. merriami is very similar, and the habitat is a bit more typical for it, but it is usually darker and around 9 cm, besides, I am not sure Madera Canyon is within its range.

    • vdinets 10 years ago

      The second one is, I think, P. maniculatus. P. leucopus is never that orange, and all other Peromyscus have tail longer than h&b (and larger ears, too). For a second I considered fulvous harvest mouse, but the measurements don’t fit.

  3. Author
    Mike Richardson 10 years ago

    Many thanks Vladimir, I really appreciate your input. I’m pretty sure of the measurements of the first one as I manage to catch it and get rough tail and body length with a pocket ruler!

    • vdinets 10 years ago

      In this case I think you can be reasonably certain it’s P. eremicus 🙂

  4. Fiona Reid 10 years ago

    I agree with Vladimir about the second mouse, but the first could also be P. boylii. If you have pictures of the tip of the tail that would help, as it is a little tufted in boylii and not in eremicus. They do occur in Madera Canyon but you may be at too low elevation in Box Canyon,

  5. Author
    Mike Richardson 10 years ago

    Unfortunately I only have one photo of the first mouse although I don’t remember it having a tuft. I would guess that the elevation where I saw the mouse would be approx. 3,000 ft. which I understand is usually the lower limit of P. boylii.

    Thanks for the help.

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