Mustela frenata, or long-tailed weasel, have dark brown dorsal fur and a much lighter abdomen (3). Most populations undergo two molts annually however populations found in southern North America do not (3). As their common name suggest their long, black-tipped tail makes up 44-70% of their total length (2)(3). The rest of M. frenata’s body shape is typical for the family; with short legs and an elongated body and tail (3). Mating occurs in the summer and litters of 4-9 young are raised by both parents (1). M. frenata are generalist predators; feeding on small to medium sized mammals and showing a affinity for bird eggs (3).

(1) Ahlbron, G. (n.d.). Life history account for Long-tailed Weasel (pp. 1-2) (United States of America, California Department of Fish and Wildlife, California Interagency Wildlife Task Group) (M. White, Ed.). CA.

(2) Jameson, E. W., Jr., & Peeters, H. J. (2004). Mammals of California (Revised ed.). Berkeley, CA: University of California Press.

(3) Sheffield, S. R., & Thomas, H. H. (1997). Mustela frenata. Mammalian Species, 1-9.

(Photograph) Alden M. Johnson © California Academy of Sciences