Mammals
Agassiz
National Wildlife Refuge, established in 1937, National
Wildlife Prior to colonization 81 species of mammals were
found in Minnesota. Today there are 74 resident species
within the state. Over half, 49 species, can be found on the
refuge, because of the plant diversity which provides food
and shelter.
Mammals
on the refuge range I size from the small pygmy shrew to the
large Northwestern moose. Mammals are important in the
ecology of the refuge. Herbivores such as mice, squirrels,
rabbits, hares, muskrats and deer change plant food energy
into animal protein which then becomes available to predators
such as mink, gray wolf, hawks and owls. Some of the mammals
such as raccoon, red fox and coyote play the role of
scavengers, as well as predators.
Many
mammals are fairly common and are most active during early
morning or late evening. Others are rare, secretive, or
appear only at night. Mammals select habitat which provides
good cover making obser-vation more difficult than birds.
Some of the best ways to determine a mammals presence is to
look for their tracks, droppings, dens, holes, beds, or
mounds. Binoculars and a picture field guide will help you
identify mammals. Should you observe an unlisted, rare, or
uncommon mammal species, please contact the refuge office.
Scientific
names and the order in which they appear follow Jones, et.
al., “Revised Checklist of North American Mammals North
of Mexico, 1975;” while common names are taken from Burt
and Grossenheider “A Field Guide to the Mammals,
1962.”
Moose
Four
subspecies of moose are recognized in North America. Agassiz
is home to the third largest subspecies, the Northwestern.
Standing six feet tall from the shoulders, bulls weigh from
800 to 1100 pounds and cows weigh from 600 to 800 pounds.
Moose
are the largest member of the deer family. Both sexes have a "bell" attached
to the throat, which is a distinct pendulous flap of skin and hair.
Rutting,
or breeding season, lasts from mid-September through October.
After an eight month gestation period cows calve in late May
and June, usually producing a single calf, weighing between
25 to 35 pounds. For at least the first year of their life
calves are dependent on the cow for protection, warmth, and
in the winter for gaining access to food and shelter by
following her trail through the snow. Normal winter
population of moose on the refuge and the three adjoining
state wildlife management areas is 250 animals. Willow is
their preferred food, but in summer they also feed on
submerged aquatic plants.
Moose
can be observed throughout the refuge and state areas. Cows
with calves are best observed in June and bulls are
frequently observed during the breeding season. For your
safety do not approach cows with calves or bulls during the
breeding season.
Wolf
In
February 1982, establishment of a wolf pack on Agassiz was
confirmed. Since 1982 a second pack has been established on
the refuge and adjoining state wildlife management areas.
Although secretive, wolves may be observed throughout the
year .
Gray
wolves are divided into five subspecies in North America.
Wolves in Minnesota are considered to be the Great Plains
Wolf subspecies. Adult wolves stand 30 inches high at the
shoulder and weigh from 60 to 120 pounds. Color varies from
almost white in the arctic to nearly black, with gray being
most common. The number of wolves in a pack ranges from 6 to
12 animals. The pack is composed of a dominant breeding pair
of adults, which mate for life, and offspring from previous
years. Four to seven pups are born in late April. Pup
mortality exceeds 50% during the first year of life. A wolf
pack’s territory varies from 50 to 150 square miles
depending on food availability.
Gray
wolves were originally the most widely distributed land
mammal in the world, living on all four northern hemispheric
continents. Gray wolves lived throughout North America before
colonial settlers arrived. With settlement, the wolf was
eradicated throughout most of its former range. Consequently,
it was protected under the Endangered Species Act of 1973.
Before 1973, there were about 650 wolves in Minnesota. As of
1997, their numbers have increased to about 2000. This
increase has prompted the U.S. Fish and Wildlife Service to
consider removing the gray wolf from the Endangered Species
List in Minnesota and the Great Lakes Area.
White-tailed
Deer
White-tailed
deer are one of the more commonly observed animals on the
refuge. Annual deer population ranges from 1,000 to 3,500
deer on Agassiz and the three adjoining state wildlife
management areas. Look for deer in all types of habitats.
Fawns are born in late May or June.
Fisher
Fisher,
a tree dwelling weasel larger than the ground living weasel
species, is about the size of a red fox. Pine marten, a close
relative to the fisher, is smaller and lives in the
coniferous forest of Minnesota. Color of the fisher is dark
brown, almost black, with a grizzled appearance caused by
white bands on the guard hairs. The tail is long, hairy and
bushy. One to four young are born in late March or early
April. Although fisher have lived on the refuge for many
years, the first documentation of fisher born on the refuge
was in June of 1993. Fishers are solitary, except during
mating and when rearing their young. Fishers live mainly in
the hardwood forest and are rarely observed.
River
Otter
River
otters are large weasel-like mammals, three to four times the
size of a mink. Otters present a sleek appearance with their
fairly small head, long slender body and long, thick tapering
tail with short hair. Fur color is dark brown, a bit lighter
on the underside, and often grayish or silvery on the throat.
The otter's eyes are located toward the front of the face
giving better frontal vision. Usually 2 to 4 young are born
in April or May. Otter crossings between pools and ditches
can be observed along the roads and trails. Otters can be
observed in wetlands, especially ditches, throughout the
refuge.
Muskrat
Muskrat
are rich brown in color with a silver colored belly and a
long, black, naked tail. Muskrat are sometimes confused with
beaver, but beaver are larger and have a flat, broad tail.
Five to six young are born per litter with some females
producing up to three litters per year.
Muskrat
begin building houses in September out of cattail, bulrush,
and other wetland vegetation. Their houses provide loafing
and resting sites to Canada geese and ducks which nest on top
of muskrat houses.
Mink
Mink
may be observed in any of the wetlands. Mink and otters look
similar, except mink are smaller in size and have a hairy,
bushy tail. In the winter, mink feed almost exclusively on
muskrat.
Coyote
Coyote,
sometimes referred to as a "brush wolf", look like
a medium-sized dog and are gray or reddish gray, with rusty
legs, feet, and ears. Throat and belly are white color. Five
to ten pups are born in April. Since the gray wolf became
established, coyote numbers have declined and are rarely
observed.
Red
Fox
Red fox
have the appearance of a small dog. Four to nine pups are
born in April. Young fox disperse from the parent's territory
in September - October. Red fox may be observed on roads,
trails and dikes or in any of the upland habitats throughout
the year.
Complete
Mammal Listing
Masked
shrew (Sorex cinereus)
Water shrew (Sorex palustris)
Arctic shrew (Sorex arcticus)
Pygmy shrew (Microsorex hoyi)
Short-tailed shrew (Blarina brevicauda)
Star-nosed mole (Condylura cristata)
Little brown myotis (Myotis lucifugus)
Big brown bat (Eptesicus fuscus)
Red bat (Lasiurus borealis)
Hoary bat (Lasiurus cinereus)
Eastern cottontail (Sylvilagus floridanus)
Snowshoe hare (Lepus americanus)
White-tailed jackrabbit (Lepus townsendii)
Woodchuck (Marmota monax)
Thirteen-lined ground squirrel
(Spermophilus tridecemlineatus)
Franklin's ground squirrel
(Spermophilus franklini)
Eastern chipmunk (Tamias striatus)
Gray squirrel (Sciurus carolinensis)
Fox squirrel (Sciurus niger)
Red squirrel (Tamiasciurus hudsonicus)
Northern flying squirrel (Glaucomys sabrinus)
Plains pocket gopher (Geomys bursarius)
Beaver (Castor canadensis)
Deer mouse (Peromyscus manicuslatus)
White-footed mouse (Peromyscus leucopus)
Gapper's red-backed vole
(Clethriononys gapperi)
Meadow vole (Microtus pennsylvanicus)
Muskrat (Ondatra zibethicus)
*Norway rat (Rattus norvegicus)
House mouse (Mus musculus)
Meadow jumping mouse (Zapus hudsonius)
Porcupine (Erethizon dorsatum)
Coyote (Canis latrans)
Gray wolf (Canis lupus)
Red fox (Vulpes vulpes)
Gray fox (Urocyon cinereoargenteus)
Black bear (Ursus americanus)
#Raccoon (Procyon lotor)
Fisher (Martes pennanti)
Ermine (Shortailed weasel) (Mustela erminea)
Least weasel (Mustela nivalis)
Long-tailed weasel (Mustela frenata)
Mink (Mustela vison)
Badger (Taxidea taxus)
Striped skunk (Mephitis mephitis)
River otter (Lutia canadensis)
Bobcat (Lynx rufus)
@American elk (Cervus elaphus)
White-tailed deer (Odocoileus virginianus)
Moose (Alces alces)
* Exotic species
# Not native to area before colonial settlement
@ Not a resident mammal of the refuge
