|MAMMALS OF THE BALTIMORE - WASHINGTON AREA
|THE METROPOLITAN NATURALIST
Eastern Grey Squirrel (Sciurus carolinensis)
The Grey Squirrel is our most visible squirrel. These little fellows
live in just about every backyard. In the summer this squirrel builds
large leafy nests on branches of trees, where young are raised. In
the winter they often live inside hollow trees or branches.
In addition to the Grey Squirrel there are five other squirrels in our
area that are not pictured here:
- The Eastern Fox Squirrel (Sciurus niger) looks a lot like a large
Grey Squirrel. These are uncommon in our area, but I have seen
a few. On the Eastern Shore, a subspecies of the Fox Squirrel
called the Delmarva Fox Squirrel (Sciurus niger cinereus) is on
the endangered species list.
- The Southern Flying Squirrel (Glaucomys volans) is much more
common than most realize. This small squirrel is nocturnal and
rarely seen except when it wanders into a house, where it
sometimes nests in attics.
- The Red Squirrel (Tamiasciurus hudsonicus) is a small squirrel of
pine forests. The small Red Squirrel is seen jumping high
up in pine trees while it chatters loudly.
- The Eastern Chipmunk (Tamias striatus) is a small striped squirrel
usually seen scurrying on fallen logs or on the ground.
- The Groundhog or Woodchuck (Marmota monax) - yes these are
technically squirrels, they are in the the family Sciuridae with the
other squirrels. Groundhogs usually prefer open areas, but are
sometimes seen in woods. They are often seen on the sides of
highways grazing on the grasses and weeds.
Voles are small mouse-like rodents, with tiny bead-like eyes. Voles
make runways through tall grass or in the leaf litter on the forest
The vole in the picture, I believe, is a Pine Vole (Pitymys
pinetorum). The Pine Vole is found in forested areas, often in
deciduous forest. This picture was taken in a deciduous forest in
Gunpowder Falls State Park.
The Meadow Vole (Microtus pennsylvanicus) is common in open,
grassy areas. I have found Meadow Vole nesting under boards in
tall grassy areas.
White-tailed Deer (Odocoileus virginianus)
These hoof prints are a familiar site in the Baltimore-Washington
Metropolitan area. Over the past thirty years deer have
recovered remarkably from overhunting and habitat destruction.
Deer were virtually eliminated from our area in the early 20th
century. A reintroduction program was started, I believe in the
1930's, by the Department of Natural Resources. By the early
1980's deer had rebounded to the point of being considered
pests in many areas, damaging crops and gardens and defoliating
the forest undergrowth.
Shrews are small mouse-like animals that are very common throughout our area.
They are found in woods, wetlands, fields, backyards, and waste areas. Shrews
differ from mice in having a long pointed snout, very small eyes, and hidden
ears. Unlike mice, which are in the order Rodentia, the Rodents, shrews are
classified in the order Soricomorpha, the Insectivores. Shrews have sharp,
pointed stabbing teeth, while mice and other rodents have flat gnawing front
Shrews are primarily carnivorous, being vicious hunters often tackling animals
larger than themselves. They are also known to eat some vegetable matter, and
some are reported to be fond of many types of seeds.
Some shrews are venomous, secreting toxic peptides in their saliva that appear
to paralyze or even kill prey. In the Baltimore-Washington area the very common
Short-tailed Shrew is known to be venomous. The toxic saliva is relatively
harmless to humans, but the bite has been reported to cause some pain and
swelling in the area of the bite.
Short-tailed Shrew (Blarina brevicauda)
Least Shrew (Cryptotis parva)
We have a large variety of mammals in our area, but most are rarely seen because of their nocturnal and/or
secretive habits. Some of the larger mammals are quite visible in suburban Baltimore and Washington, DC. In many
areas, animals are not hunted anymore and many have lost their fear of man. In my suburban yard I often see
Eastern Cottontail Rabbits, White-tailed Deer, Red Fox, Raccoon, Grey Squirrel, Chipmunk, Groundhog, Bats
(unidentified), and Cats. Tracks in the mud on the sides of streams or in the snow give away the presence of the
larger animals even when we do not see the animals themselves. Many of the smaller mammals, such as mice,
voles, and shrews, are rarely seen but might be plentiful. These smaller mammals are under a constant threat from
Hawks, Owls, Fox, and other predators, so they stay hidden. Often a rustling in the leaves as the animal scurries
away when we pass by is the only sign we have that an animal is there.
The small mammals can be difficult to study. Occasionally, turning boards and sheet metal will reveal a nest or
expose runways. Boards can be strategically placed to provide cover. I wore a garden glove while checking boards
so I could pick up and identify small animals found under the boards. Live trapping can be used for some animals.
A drift fence with pitfall traps can help to find other animals.
When listing numbers of species in each group of mammals I usually use the words "approximately" or "about". I do
this because changes in classification, lack of range information, and changes in ranges of animals make the exact
number difficult to obtain.
Some of the mammals in our area are:
Shrews - about 7 species.
- Northern Short-tailed Shrew (Blarina brevicauda)
- Smoky Shrew (Sorex fumeus)
- Southeastern Shrew (Sorex longirostris)
- Masked Shrew (Sorex cinereus)
- Longtail Shrew (Sorex dispar)
- Northern Water Shrew (Sorex palustris) - Western Maryland and Western Virginia only
- Pygmy Shrew (Microsorex hoyi)
- Least Shrew (Cryptotis parva)
Moles - 3 species.
- The Eastern Mole (Scalopus aquaticus) is common in grassy areas and lawns.
- Starnose Mole (Condylura cristata)
- Hairytail Mole (Parascalops breweri)
Bats - 10 to 12 species.
- Little Brown Myotis
- Indiana Myotis
- Small-footed Myotis
- Keen Myotis
- Eastern Pipistrel
- Big Brown Bat
- Red Bat
- Hoary Bat
- Evening Bat
Weasels and Mink - 4 species.
- Least Weasel (Mustela rixosa)
- Shorttail Weasel (Mustela erminea)
- Longtail Weasel (Mustela frenata)
- Mink (Mustela vison)
Mice - 3 or 4 species.
Jumping Mice - 2 species.
Rats - maybe 2 species.
Eastern Woodrat (Neotoma floridana) - one species.
Rice Rat (Oryzomys palustris) - one species.
Southern Bog Lemming (Synaptomys cooperi) - one species.
Boreal Redback Vole (Clethrionomys gapperi) - one species.
Striped Skunk (Mephitis mephitis) - one species.
Muskrat (Ondatra zibethica)
Nutria (Myocastor coypus)
Fox - 2 species, red fox (Vulpes fulva) and Grey Fox (Urocyon cinereoargenteus).
River Otter (Lutra canadensis)
Raccoon (Procyon lotor)
Opossum (Didelphis marsupialis)
Bobcat (Lynx rufus)
Black Bear (Ursus americanus)
Coyote (Canis latrans)
Track of a Raccoon (Procyon lotor)
The distinctive hand-like print of a raccoon's front foot at the side of a
stream. The raccoon is known for it's ability to open trashcan lids and
making a mess of litter while taking a free meal of leftovers. The
raccoon is a scavenger, eating berries, grubs, and small animals when
they can catch them. They also have been known to raid birds nests to
eat the eggs.