Key to North American species of Marmota

Return to Keys

This key to the North American species of Marmota is borrowed from Frase and Hoffman (1980). Images and maps were added for clarity.

1

• Dorsal pelage soft; guard hairs black-tipped, with subterminal light band. Black "cap" on dorsal surface of head extending uninterrupted from nose to neck. Found only in northern Alaska and adjacent Yukon .....Alaska Marmot (Marmota broweri)

• 

  Alaska Marmot (Marmota broweri) photographed by Robert Weeden near Toolik Field Station, Brooks Range, Alaska.

• 

  Range of the Alaska Marmot (Marmota broweri)

• Dorsal pelage coarse; many guard hairs with light tips, or else uniform dark brown or black. Black or brown dorsal surface of head interrupted by white markings on face, or else top of head uniform brown or grizzled . . . . . 2

2

Return to couplet #1

• Entire pelage dark brown; guard hairs without light tips; occasionally with white spots on ventral surface. Posterior border of nasals deeply V-shaped. Found only on Vancouver Island.....Marmota vancouverensis

• 

  Marmota vancouverensis photographed by Adam Taylor on Vancouver Island, Canada.

• Not as above . . . . . 3

3

Return to couplet #2

• Dorsal surface of head uniform grizzled blackish or dark brown; sides of neck grizzled brown, not different from rest of pelage on side. Upper tooth rows approximately parallel. Postorbital processes project along a line drawn across their bases at right angles to the long axis of the skull. Usually only four pair of mammae.....Woodchuck (Marmota monax)

• 

  Woodchuck (Marmota monax) photographed by sfreeman7 in Toronto, Ontario, Canada.

• 

  Holotype: 78360. Marmota monax rufescens. Adult male. Wilmington, Middlesex County, Massachusetts. Collected 19 April 1896. Dorsal view of the skull.

• 

  Holotype: 78360. Marmota monax rufescens. Adult male. Wilmington, Middlesex County, Massachusetts. Collected 19 April 1896. Ventral view of the skull.

• 

  Range of the Woodchuck (Marmota monax)

• Dorsal surface of head black to brown, usually interrupted by white facial markings; sides of neck whitish to buffy, lighter than rest of pelage on side. Upper tooth rows more or less divergent anteriorly. Postorbital processes usually project back of a line drawn across their bases at right angles to the long axis of the skull. Usually five pair of mammae . . . . . 4

4

Return to couplet #3

• Sides of neck buffy to yellowish; feet hazel-brown to buffy; rarely dark brown and never black (except in melanistic specimens); pad in middle of sole of hind foot oval (see also Howell, 1915; Hoffmann et al., 1979). Fronto-nasal and fronto-premaxillary sutures usually forming distinct arch across rostrum.....Yellow-bellied Marmot (Marmota flaviventris)

• 

  Yellow-bellied Marmot (Marmota flaviventris) photographed by Rick Overson in Custer Gallatin National Forest, Montana.

• 

  Ventral surface of sole of hind foot of Marmota flaviventris, showing oval shape of posterior pad. Borrowed from Frase and Hoffman (1980).

• 

  Holotype: 186520. Marmota flaviventris luteola. Adult male. Woods Post Office, Medicine Bow Mountains, Albany County, Wyoming. Collected 13 August 1888. Dorsal view of the skull.

• 

  Range of the Yellow-bellied Marmot (Marmota flaviventris)

• Sides of neck whitish to gray or cream; never buffy; feet black to dark brown; pad on hind foot near edge of sole, subcircular. Fronto-nasal and fronto-premaxillary sutures usually forming a fairly straight line across rostrum . . . . . 5

• 

  Holotype: 137319. Marmota caligata caligata. Adult male. Montague Island, Alaska. Collected 24 May 1905. Dorsal view of skull.

• 

  Holotype: 90518. Marmota olympus. Adult male. Olympic Mountains, Clallam County, Washington. Collected 27 August 1897. Dorsal view of the skull.

5

Return to couplet #4

• Head and forepart of body mainly black and white in color; feet black. Not found in Olympic Mountains of western Washington.....Hoary Marmot (Marmota caligata)

• 

  Hoary Marmot (Marmota caligata) photographed by Eemeli Haverinen in Denali National Park, Alaska.

• 

  Range of the Hoary Marmot (Marmota caligata)

• Head and forepart of body mainly brown, mixed with white guard hairs. Feet dark brown. Found only in Olympic Mountains of western Washington.....Olympic Marmot (Marmota olympus)

• 

  Olympic Marmot (Marmota olympus) photographed by Mike Merchant in Clallam County, Washington.

• 

  Range of the Olympic Marmot (Marmota olympus)

References

Frase BA, Hoffmann RS. 1980. Marmota flaviventris. Mammalian Species (135):1-8.

Hoffmann RS, Koeppl JW, Nadler CF. 1979. The relationships of the amphiberingian marmots (Mammalia: Sciuridae). Occasional Papers of the Museum of Natural History, University of Kansas 83:1-56.

Howell AH. 1915. Revision of the American marmots. North American Fauna 37:1-8