Wisconsin Rat, Mouse, and Vole Identification Key! (Non-Herp)
Wisconsin Rat, Mouse, and Vole Identification Key
*Adult Specimens Only.
1. Ears Large and Naked, Tail Long to Very Long
1A. Total Length 11.81 in. or Greater……………………………………………..Brown (Norway) Rat, Rattus norvegicus.
1B. Total Length Less Than 11.81 in.
1Ba. Tail Extremely Long, Hind Feet Very Elongated and Large
1Ba-1. Tail Tip White………………………………….Woodland Jumping Mouse (Napaeozapus insignis).
1Ba-2. No White Tail Tip……………………………..Meadow Jumping Mouse (Zapus hudsonius).
1Bb. Tail of Average Length, Hind Feet Larger Than Fore Feet but not Oversized
1Bb-1. Pelage Color Sharply Contrasting Between Dorsum and Underside.
1Bb-1a. Tail Length Somewhat Shorter. Demarcation Line on Tail Not As Sharply Defined……………………………………….White-Footed Mouse (Peromyscus leucopus).
1Bb-1b. Tail Length Somewhat Longer. Demarcation Line on Tail More Sharply Defined…………………………………………………Deer Mouse (Peromyscus maniculatus).
1Bb-2. Pelage Color Solid or Uniform, or Not Sharply Contrasting Between Dorsum and Underside.
1Bb-2a. More Slender Build Overall. Tail More Hairy. Indistinct Dark Dorsal Stripe Present. Upper Incisors Distinctly Grooved………………………………………………Western Harvest Mouse (Reithrodontomys megalotis).
1Bb-2b. Moderate to More Heavy Build Overall. Tail Naked or Much More Sparsely Haired. Indistinct Dark Dorsal Stripe May or May Not Be Present. Upper Incisors Not Distinctly Grooved………………….House Mouse (Mus musculus).
2. Ears Short and Rounded, Tail Short to Very Short
2A. Grizzeld Pelage. Tail Very Short and Not Longer Than the Hind Feet. Well Defined Squamosal Crest. Thick Rostrum. Upper Incisors Slightly Grooved………………………Southern Bog Lemming (Synaptomys cooperi).
2A-1. Grizzled or Solid Pelage. Tail Short But At Least Twice the Length of the Hind Feet. No Well Defined Squamosal Crest. Upper Incisors Not Grooved.
2A-1a. Eyes Very Small and Beady. Claws on Fore Feet Large. Mole-Like in Appearance…………………………………………………….Woodland Vole (Microtus pinetorum).
2A-1b. Eyes Larger but Still Beady. Claws on Fore Feet Small.
2A-1bb. Yellowish to Rust Red-Orange on Face and Anterior Pelage…………………Rock (Yellownose) Vole (Microtus chrotorrhinus).
2A-1bc. More Grizzled or “Salt and Pepper” Pelage, Although Other Skull Characteristics May Be Preferred………………Prairie Vole (Microtus ochrogaster).
2A-1bd. Pelage Much Less Grizzled or More Solid, Although Other Skull Characteristics May Be Preferred……………………..Western Meadow Vole (Microtus drummondii).
2A-1be. Pelage with Rusty Red or Orange on Dorsum, Lighter Gray or Silvery Along Flanks………………………………………………………Southern Red-Backed Vole (Clethrionomys gapperi).