NPS Photo Featured FriendsMeet some of the common mammals seen in Minute Man National Historical Park 
NPS Photo North American BeaverCastor canadensis If you’ve ever seen a beaver swimming while gnawing on branches or building up his lodge, you know it’s pretty special. Beavers intermittently set up shop downstream of the North Bridge and in the Mill Brook and Elm Brook areas… and they’re hard to miss when they’re here. The North American Beaver is the largest rodent throughout the US, weighing in between 35 and 80lbs in adulthood and measuring 2-3 feet in length, PLUS another foot and a half of tail! Beavers use that large flat tail to swim, balance and might slap it on the surface of the water to sound an alarm or scare you off. In addition to their tail, beavers also have other specially adapted features that make life in the water easier, including webbed feet and oil glands to keep their fur water resistant. When on land, beavers use their large front teeth, which grown throughout their lives, to bring down trees. They then build dams and lodges with smaller tree trunks and large branches. Beaver dams are incredibly important within many ecosystems… the resultant flooding of a river or stream creates wetlands; key habitat for many other species, including fish and migrating birds. Wetlands also improve water quality, enrich nutrient content in surrounding soil, reduce erosion and prevent significant amounts of sediment from flowing downstream. 
NPS Photo Eastern ChipmunkTamias striatus Perhaps one of the cutest and most prolific mammals at Minute Man (we love to watch their antics on the many rock walls around the park), the Eastern Chipmunk is also an active environmental helper. These small brown rodents, marked with black and white stripes on their backs, feed on green, flowers, berries, and nuts… lots of nuts! Chipmunks will spread the seeds from flowers, berries and trees (nuts), which allows those species to propagate. Chipmunks are adaptable little creatures and will make their homes in underground burrows, wood and brush piles, and rock walls. Because they’re so small and find themselves near the bottom of the food chain, chipmunks also build extensive tunnel systems with multiple entrances and exits to facilitate a quick getaway when predators are around. If you’re lucky, you might spot some baby chippers in spring popping their heads out of a hole at the side of the trail or out of the rock walls at the North Bridge. Chipmunks mate twice a year producing 4-5 kits each time. 
NPS Photo Eastern Gray SquirrelSciurus carolinensis Love ‘em or hate ‘em, the Eastern Gray Squirrel calls eastern Massachusetts (and basically everywhere else in the US) home sweet home. Here at Minute Man, we love watching these amazing acrobats run, roll, and leap up to 10 feet from tree to tree. Their agility is due in part to their ability to climb nose down by turning their feet to face backwards, as well as a fluffy tail which is 50% of their total body length. Eastern Gray Squirrels are moderately sized rodents, weighing about a pound and measuring up to 18 inches in length. Squirrels maintain a healthy, varied diet including insects, birds, eggs, berries and nuts. Much like chipmunks, a squirrel’s preference for nuts means they contribute significantly to forest regeneration. Because Eastern Grays are active year-round (many squirrel species hibernate), they must store food for the lean times. An individual squirrel may cash hundreds or even thousands of nuts by burying them in the ground. But sometimes they just pretend to bury a nut to trick a nearby bird or squirrel. All those nuts and all that subterfuge means a squirrel might not remember the location of every cache, which allows those nuts to grow into beautiful trees. Squirrels, as you might have guessed, prefer to live in mixed forests, but they are highly adaptable and may thrive in most any environment. That adaptability is why squirrels have learned to live in human homes, as their natural forest habitats are destroyed by cities, towns and suburban sprawl. Of note, while the squirrels we see here are Eastern Grays, they do come in multiple color phases, including white and black. These variations are more common in urban and suburban areas. 
Fort Drum Military Installation, Fort Drum, NY. Little Brown BatMyotis lucifugus The Little Brown Bat, so little, so brown, so unassuming… The truth is, these guys deserve a lot of respect. Have you ever taken the time to consider bats are the only mammal that can fly? Bats are also important parts of a forest ecosystem, serving as prey species for many predators, including owls, foxes and snakes. More importantly to us humans, Little Brown Bats eat a lot of insects, including mosquitoes. Each summer evening, using echolocation, a bat will eat half its body weight in bugs! A mother bat will consume its whole body weight worth of insects each night. August is mating season and pups are born in October. Baby bats grow rapidly and are able to fly just 3 weeks after being born. An adult Little Brown Bat weighs less than ½ ounce, but it’s wing spread is 8 to 11 inches. Little Browns, which may also be reddish or blond, are not territorial and live in large colonies of more than 150,000, though the average is just shy of 10,000. Unfortunately, the population of Little Brown Bats has declined, particularly in the eastern US, due in large part to a fungal infection called White Nose Syndrome. Pesticides, mining and deforestation are also impacting populations. To learn more about the Little Brown Bat, check out this article from the NPS Integrated Resource Management Application: https://irma.nps.gov/Datastore/DownloadFile/629595 
NPS/Neal Herbert MuskratOndatra zibethicus Not a rat. Again, the Muskrat would like you to know he is not a rat, but rather a member of the vole family. This sweet little marsh dweller must however, own up to being pretty stinky. The Muskrat got its moniker for having both a rat like tail and a strong, musky scent. While weighing in at only about 4 pounds and measuring a foot in length, Muskrats are sometimes mistaken for their larger cousin, the beaver, because they share similar habitats and also build lodges in wetlands. Here in the park, you may see Muskrats in the Concord River, Mill Brook and Elm Brook. If they see you and dive down, don’t expect to see them again or in the same spot. A Muskrat can stay underwater for up to 20 minutes and uses it’s partially webbed feet to swim at 3 miles per hour. 
NPS Photo/ Tim Raines Red FoxVulpes vulpes Celebrated in literature and folklore as a trickster archetype, the red fox may in fact be a smart and charming as its mythical counterpart, but nowhere near as troublesome. In fact, Foxes often get blamed for things they didn’t do. While these small canines, weighting 10 to 15 pounds, can and do live in and around suburban areas, they are shy and don’t often get near homes. That said, don’t invite them to the cookout. Clean the BBQ, bring in the dog food, and if you notice a fox frequenting the neighborhood, maybe bring in the bird feeder that’s attracting prey species like squirrels and other rodents. Foxes have great hearing and will likely hear a rodent moving below the snow or soil before they see it. Foxes prey on rodents, rabbits, and birds as well as fruit. Because of this diet, the Red fox makes its home in open areas on forest edges, wetlands and overgrown fields. You can spot a red fox in the fields or trails of Minute Man. You’ll recognize the bright rusty color with that characteristic white tail tip. But, fun fact, not all Red Foxes are red (are you sensing a theme here?), some will have a significant amount of grey or black fur. An animal displaying this color phase is called a cross fox and might look more like a gray fox, which we have in eastern Massachusetts, but you’ll know it’s a Red because it’ll still have that white tail tip. 
NPS Photo Virginia OpossumDidelphis virginiana O, the Opossum! A creature that doesn’t get nearly the love and respect it deserves. There also isn’t enough page space to give this critter the credit it deserves here, so make sure you pop Opossum into your search engine when you are in need of a little awe and inspiration. And yes, it’s Opossum- not Possum- a possum is a totally different animal that lives in Australia. The Virginia Opossum you might spy along the battle road trail is distinguishable by its milky white fur, round, black ears, and pink nose, feet and tail. Now, time for the fun facts! Opossums have an opposable thumb and prehensile tail making them adept climbers, though they don’t really like to climb. Opossums are solitary, nocturnal, slow movers who spend their time eating bugs, snails and slugs. One of the Opossum’s favorite snacks is the tick. Some scientists estimate a single Opossum will consume upwards of 5,000 ticks in one season. Despite that icky diet, the Opossum has NO body odor! None! This is likely due to the fact that they lick themselves constantly to help regulate temperature. Cooler than that (see what we did there?), the Opossum has more teeth than any other land mammal in North America- they have 50 chompers! An opossum will bare those 50 sharp teeth and hiss when threatened, but they are shy and will rarely if ever actually bite out of fear. If you’re not scared and don’t move away, an Opossum may play dead (playing possum), but sadly this is not a clever defense mechanism, it’s an involuntary stress response. This catatonic state can last minutes or hours and an Opossum will likely drool and defecate involuntarily while “out”. This does cause predators to think they are dead and rotten and thus leave them alone. Stress passing out aside, Opossums are pretty smart. This species is second only to humans when it comes to remembering where food is, and as pets they can learn their names, use a litter box, snuggle and learn the routines of their owners. Finally, and most impressively we come to the reproduction of Opossums. A female will have two litters of 8 to 12 babies each year. Being marsupials, the mother will keep the babes in her pouch for 2 months then carry them on her back for another month or so. Amazingly, she’ll do so on her own as the male Opossum leaves after mating. Remember that recommendation to visit a search engine? You have to read more about the harrowing first months for baby opossums! All this and Opossums live a short life, just 1 to 2 years. 
Kathy Dia White Tailed DeerOdocoileus virginianus A frequent visitor to the farm fields near Meriam’s corner and the open fields by the Minute Man Visitor Center, the White-Tailed Deer is probably the largest mammal you’ll spot in the park. Size varies widely for this species. A male can be up to 3 and a half feet tall and weigh as much as 300 pounds, though the largest recorded buck in North America was more than 500lbs! Females typically weigh 100 to 200 pounds. You can tell adult males from females because they will wear an antler crown much of the year. These antlers are shed and regrown annually, so it may be a bit tougher in late winter and early spring when the males don’t have their spikes. Interestingly, a very small percentage of female deer will also grow antlers. More iconic than the antlers though, is the deer’s long tail with bright white fur on its underside. You’ll see the flash of white as the deer flees danger (you). The tail is not so much a flag of surrender as it is an alert to other deer. The warning system, ability to move at high speed and great skill in hiding seem to work because while these deer are a prey species for predators like bears and wild cats and canines, as well as a game species for humans, the White Tail is the oldest deer species, predating the last ice age. Do help them survive into future epocs by observing speed limits on roads surrounding the park, and keep in mind that where you see one deer, you’re likely to see more.
Mammal Lists And LinksLearn more about natural resources at Minute Man by visiting the Northeast Temperate Inventory & Monitoring website. Minute Man is a designated place with multiple projects on iNaturalist, an on-line citizen science database. Help the park track all wild species (mammals, bird, insects, plants, etc.) and behavior by adding your observations to iNaturalist whenever you visit. To learn more about non-NPS citizen science initiatives, check out this article from the National Park Service. |
Last updated: December 8, 2021