Richardson's Ground Squirrel - Spermophilus richardsonii
Global Rank:
G5
State Rank:
S5
Agency Status
USFWS:
none
USFS:
none
BLM:
none
CFWCS Tier:
3
General Description
The Richardson ground squirrel is a medium-sized ground squirrel of rather uniform coloration. It is buffy yellow to grayish in color. The tail is about one-fourth of the total body length and is blackish to buff with whitish hairs on the outer edges and end. Adults are 7 to 9 inches long and weigh 11 to 18 ounces (Montana Dept. of Agriculture 1985?).
Distribution
Resident Year Round
Observations in Montana: 285
Montana Counties
Blaine, Broadwater, Cascade, Chouteau, Fergus, Gallatin, Garfield, Glacier, Hill, Jefferson, Judith Basin, Lewis and Clark, Liberty, Madison, Meagher, Musselshell, Park, Petroleum, Phillips, Pondera, Roosevelt, Sheridan, Stillwater, Sweet Grass, Teton, Toole, Valley, Wheatland, Yellowstone
Migration
Non-migratory. May exhibit emigration/dispersal movements.
Habitat
Ocuupies open well-drained land, prairies, and pastures. Can occur on arid shrub steppe. Less well-adapted to arid shrub-steppe than is S. elegans.
Food Habits
Primarily herbivorous. Eats leaves, flowers, and seeds of grasses and forbs. Domesticated cereals when available. Stores food in burrow. Will use insects and carrion.
Ecology
Allopatric distrib. with S. columbianus from Canada border south to MADI and BEAV. S. richardsonii and S. columbianus sympatric & even syntopic (along w/ S. armatus & S.elegans) in BEAV & MADI (maybe JEFF & BROA).
Reproductive Characteristics
One litter annually, beginning as yearlings. Females typic- ally mate 3-5 days after emergence. Most recent studies show gestation to be 22.5 days. Mean litter size at emerg- ence from burrow--min 4.9, max 8.3.
Citations & Sources