Mammals are warm-blooded mammals characterized by their ability to produce milk for their young and (usually) give live birth. Mammals have skin, usually covered in hair or fur. From rodents to deer, and foxes to bats, mammals are diverse and important animals to the ecosystem of Kenilworth Aquatic Gardens. At the park, when you see muskrats swimming through the marsh or foxes on the boardwalk remember that each species plays a vital and unique role in the habitat. Different mammals eat different foods, are eaten by different species, behave in different ways, and are active at different times.
Muskrat in the water
Tim Ervin
Rodents
The order Rodentia has more species in it than any other order of mammals. Most mammals during the time of the dinosaurs were likely similar to today’s rodents, small animals that lived mostly in ground burrows. Rodents are characterized by a pair of continuously growing teeth in each their upper and lower jaw. Because of these teeth, they are voracious chewers, a quality which impacts their ecosystem heavily through habitat engineering or other mechanisms.
Muskrat
The muskrat has short legs and a compact body up with a scaly tail is flattened vertically and can be as long as the body. The eyes are small, and the ears are nearly concealed by fur, which ranges in color from reddish to blackish brown and consists of a short, soft underfur heavily overlaid with long, stiff, glossy guard hairs. Marshes are the usual habitat of muskrats, but they also live in wooded swamps, lakes, and streams, where they build sizable lodges of cattails, sedges, and other vegetation.
Beaver in the snow
Eric Trefney
Beaver
Beavers are North Americans largest rodents; these rodents are recognized for their paddle like tails. Adult beavers typically weigh 45 to 60 pounds but have been seen to grow up to 100 pounds. Beavers are ecosystem engineers because they create, modify, and maintain habitat and ecosystems, by the help of some physical features.
Their tails are large, hard, flat covered with leathery scales and sparse, coarse hair. The tail is important both in the water and on land, it acts as rudder on the water and prop when lying down or standing up. It serves as a storage area for fat supply for the winter, also its used to slap on the surface of the water as a danger warning or creating dams and lodges.
Beavers fur consist of two different textures, short fine hairs for warmth and longer hair for waterproofing. They have castor glands under their abdomen that excrete oil for grooming and territorial purposes that they spread on their fur daily. Beavers have adapted sufficiently to live in their environments
Groundhog in a field
NPS
Groundhog
Groundhogs, such as Punxsutawney Phil are iconic symbols of United States culture and tradition. They dig extensive burrow networks in which they hibernate for the winter. Hibernation is a process in which animals slow down their heart rate, breathing, and activity to conserve energy during the winter.
Groundhogs can be considered very large ground squirrels, weighing up to 13 pounds. These fluffy rodents can climb, swim, and dig. They eat mostly green plants and are active in the early morning. Fun fact: a Groundhog burrow can be up to 66 feet long!
Grey Squirrel eating
NPS/Scott Teodorski
Eastern Grey Squirrel
Though you’re always likely to see Eastern Gray Squirrels in Kenilworth Park and Aquatic Gardens, did you know that chipmunks and groundhogs are technically squirrels as well? Gray Squirrels are important for the reproduction of certain trees, as their habit of burying acorns and other nuts (and sometimes forgetting the location of their stash) allows some trees to start growing. You may also see black squirrels in the park. These individuals are still members of the Gray Squirrel species, just with a color morph that may allow them to absorb more heat and better survive the winter season.
Deer on the path in the park
Image Credit Tim Ervin
Ungulates
Hooved mammals, such as deer, moose, and bison, are some of the largest mammals in North America (excluding bears). These animals are mostly herbivorous. Of Cervidae, the family containing deer, most members have boney horns on their heads that are often used to express territoriality or for self-defense.
White-tailed Deer
White-tailed Deer are the largest wild animal in the National Capital Region. Usually weighing 150-330 pounds at most, White-tailed Deer are identifiable by the bright white underside of their tail, which they raise in alarm as they run from any potential threat. These deer change color depending on the season; in spring and summer, the White-tailed Deer sports a rich reddish-brown coat, though the red fades into more gray tones during fall and winter. Male deer, also known as bucks, grow antlers every year during the mating season. The size of their antlers depends upon the richness of nutrition available to them. Some female deer, also known as doe, grow small antlers as well, though it is not common for them to do so. In North America, deer have been an important cultural and ecological symbol for centuries. They span many habitat types, from marshland to forests and mountains, and may even be spotted chewing up the garden plants in suburban areas.
mink running through the marsh
Tim Ervin
Carnivorans
Carnivorans belong to the order of mammals that have evolved to primarily eat other animals. Despite being “carnivores,” these animals are capable of eating multiple types of foods and will often opt for whatever is most easily available, like berries and carrion. However, because of their importance in the ecosystem, predators are often called “keystone species.” Without predation, the populations of prey animals can explode, leading to overconsumption of plant species.
Mink
The American Mink is a small carnivorous mammal with a long slim body. Adult male minks often weigh about two pounds and stretch about two feet long, not including their tails. Minks embody the Shakespeare quote “though she be but little she is fierce,” with their voracious appetites and territorial natures. Exported from the United States for fur farming, the American Mink is now an invasive species in Europe. Fun fact: They can swim up to 100 feet underwater without coming up for air.
A fox standing in front of the ponds
Eric Trefney
The Red Fox
The Red Fox, so called for the reddish coloration of its fur, is widespread across the Earth’s Northern hemisphere. Though it’s a native species to North America, Europe, and Asia, it is invasive in Australia. Related to dogs, the Red Fox is very important as a general predator- eating small rodents and birds. Red Foxes don’t only eat meat though, they’re also known to enjoy fruits, nuts, berries, and grasses from time to time.
Red Foxes are most often observed close to their life-mate or family group. Young adult foxes will even stay with their parents to assist with the care of new kits. Adult foxes weigh up to 30 pounds and trot at a speed of up to 8mph.
Coyote in a field
NPS/Gianna Farrell
Coyotes
Coyotes are members of the dog family that range across The United States and Canada. Smaller than wolves, they stand about 2 feet tall at the shoulder and have a length of about 4 feet, including their bushy tails. Commonly mistaken for stray dogs, Coyotes are predators of smaller animals including rodents and birds, as well as larger animals like White-Tailed Deer. Like other wildlife, Coyotes should not be approached.
Coyotes are mostly active during the nighttime, when you might be able to hear their loud yips and howls. They fill a similar niche in the food chain as the Red Fox, and competition between these two species can be fatal for foxes. A breeding pair of Coyotes will rear their litter of 4-7 pups in well-hidden burrows or dens.
a raccoon in a tree
NPS/Schmidt, Jim
Raccoon
Few native mammals symbolize urban wildlife better than Raccoons do. Identifiable by its bushy ringed tail and iconic “burglar mask” face markings, Raccoons are successful generalists that survive well anywhere from deeply wooded areas to downtown city streets. North American Raccoons have gray and brownish coloration. They are most active at night, at which time they will forage for whatever food they can find, including animals, plants, and (their favorite food) Oreo cookies.
For their body size, Raccoons have large brains, about the size of a cat’s. Their impressive neural network density rivals that of small monkeys. They can turn their front feet 180 degrees to more easily climb down trees. Female Raccoons care for their young for up to a year, even though Raccoon pups can already forage and hunt for themselves at just two months old.
A big brown bat at rest.
USFWS/Ann Froschauer
Bat
Often either overlooked or downright spurned, bats play a big role in the ecosystem, especially for such small creatures. The only mammals capable of powered flight, bats are more closely related to pangolins and whales than they are to rodents. All bats in the mid-Atlantic region eat insects.
They are extremely important in keeping down the number of nuisance insects, such as those that bite humans or demolish crops. Some people even encourage bats to roost near their homes as a means of pest control. There are quite a few myths surrounding bats, but the truth is that they’ve been given a bad rap. Bats do not attack humans, do not frequently carry rabies, and have advanced social structures. They’re not even blind. Bats play a vital role in the pollination of iconic plants including bananas and agave. They are important to forest health and agricultural success. Of the more than 1400 species of bats, only 3 are vampires, and those bats only live in Central and South America.
The Big Brown Bat
The Big Brown Bat (Eptesicus fuscus) is the most common bat in the National Capital region. If you watch the sky at night, you may see one flying either alone or with a group of three or four of its BFFs- bat friends forever. A wingspan of 13-16 inches may sound scary, but don’t worry – these bats only eat insects. Besides they only weigh ½-¾ of an ounce; that’s less than a single AA battery. They have brown fur on their bodies and rounded black ears. Big Brown Bats usually hibernate in caves during the winter.
Hoary Bat
NPS
Hoary Bat
Hoary Bats (Lasiurus cinereus) are some of the most recognizable bats in the Central-Eastern United States, thanks to their fluffy round appearance, light brown hair with black striping, and Guy Fieri-style bleached tips. They are the most widespread bat species in the Americas, stretching from Guatemala to Canada, and even being found in Iceland! Hoary Bats spend the majority of their time roosting in the foliage of trees or munching on insects.
Little brown bat on a tree
NPS photo / Mark Graham
Little Brown Bat
Once an extremely common bat in the DC region, the Little Brown Bat (Myotis lucifugus) has since grown increasingly rare. This is due to the 2006 arrival of a bat-infecting disease called White Nose Syndrome, that mostly kills social cave-roosting bats during hibernation. Little Brown Bats are good to have around, as one female can eat more 5000 mosquitos on a single night of foraging, with some bats recorded to eat 10 mosquitos a minute.
Eastern Red Bat on a tree branch
NPS
Eastern Red Bat
The Eastern Red Bat (Lasiurus borealis) is named for its notable reddish color. Despite its apparently eye-catching vibrancy, the Eastern Red Bat roosts on trees and uses its coloration to imitate dead leaves. Eastern Red Bats fly early in the evening, mostly focusing their foraging efforts on clearing, street lights, or forest edges. Eastern Red Bats may migrate South for the winter, or they may bury themselves in leaf litter and hibernate in places like the National Capital Region.
Silver-haired Bat on a tree
NPS/Sally King
Silver-haired Bat
Recognizable by silverish tips on their fur, Silver-haired Bats (Lasionycteris noctivagans) are true migrators. They hibernate during the winter in more Southern areas, including the Carolinas, and migrate as far North as Canada during the summer to rear their pups. Silver-haired Bats prefer eating moths to other types of insects, but are known to consume whatever is available, including termites and flies. Habitat loss and wind turbines are threats for this species. They will usually sleep high on trees during the summer.
