This is part of the 2020 Digital Seaside Center. For more Digital Seaside Center content, click here.

Hi everyone! Welcome back to local wildlife weekly.

There are few naturalists (and few people, really) who don’t get excited about mammals. In fact, when you press them on the matter, many naturalists– regardless of their expertise, be it birds or bugs or plants– will admit that their most profound and powerful encounter with a wild animal was with a mammal. Why, then, is mammal-watching not nearly as popular a pastime as birding, herping, or insect-collecting?

The apparent contradiction, when scrutinized, is actually no contradiction at all: the power of a mammal encounter is heightened by the animals’ overwhelming secrecy. That secrecy, in turn, makes the class largely inaccessible, unfit for a large following. As a result mammals occupy an interesting space in the naturalist’s psyche: while rarely ever the target of exploration, they remain the ultimate “holy grail” for time spent outdoors. The vast majority of mammal species in any given area fly well under the radar, and often times it seems that the best way to find them is not to be looking at all. There is a magic to the truly chance encounter, and it’s made all the more special by kindred spirit— we see ourselves mirrored in bright mammalian eyes.

Of course, there are exceptions. While most mammals are reclusive, denizens of undisturbed “wild” habitat, a select number have crossed over the bridge to thrive alongside human habitation. Here, in our backyards and open parks, mammals’ “magic” is called into question: we are quick to label them vermin or pests. Think squirrels, mice, or raccoons— even deer, lately– have they not had some telling fall from grace? Often seen as dirty and uncouth, there seems to be some unspoken idea of corruption at work: mammals, the epitome of wild perfection, have in our presence turned to beasts. Society has warped that perfect state of nature, and we recoil from its progeny: perhaps we see the same corruption in ourselves.

Between these two poles (spirit of the wild / demon of the dumpster) is a large gray area. I would contend that the species I’m profiling this week falls right in the middle– we don’t really know what to do with it. It’s a cultural icon, a garden pest, and a pudgy, adorable anomaly all at once. Maybe, recognizing this conundrum, we can finally free ourselves or preconception and bias and engage with this animal on its own terms. It’s worth a shot, at least. Enter the groundhog!

Introducing: The Groundhog!

A local groundhog at Greenwich Point Park. Photo by Brendan Murtha.

The groundhog, Marmota monax, is also called the woodchuck. I waffle back and forth on which name I prefer (both are fun) but ultimately might advocate for use of its latin name— Marmota monax is a hard one to beat. It also tells us something of the groundhog’s taxonomy, as latin names are prone to do; groundhogs are indeed a type of marmot (genus Marmota).

There are six species of marmot in North America, and the groundhog is certainly the odd-one-out. While the other five species inhabit mountainous regions in the west, denning on rocky slopes, the groundhog prefers soft soils and therefore is best suited for flat, fertile ground. It is a prolific digger, and lives in large burrows up to 30 feet long. In crafting such tunnels groundhogs turn over a massive amount of soil, which builds up outside the entrance in soft, nutrient-rich mounds. Soil turnover is important for a healthy ecosystem, as it recycles nutrients and aerates the subterranean habitat. While today groundhogs are most common in pastures and along roadsides, they have long played a role in maintaining the health of eastern meadows and prairies. The species name monax actually comes from an Algonquin word meaning “digger,” recognizing the essential role groundhogs have long played in our area.

Not only do groundhog burrows work wonders for soil health, they also provide habitat for other species after the original architects have moved on. This benevolence is fitting for an ecosystem engineer, any organism that directly creates, modifies, or destroys habitat. Such engineering is reminiscent of so-called “prairie-dog towns,” a well-known habitat created and maintained exclusively by prairie dogs on the great plains of the U.S.. The networks of burrows comprising these towns become a unique habitat all their own, supporting wildlife communities found nowhere else. While groundhogs are not communal animals, and don’t create “towns,” the general idea is the same: habitat is modified on small scales. This similarity is not a coincidence, for groundhogs and prairie dogs are close relatives: marmots are simply large ground-squirrels, like prairie dogs who've gained some weight. These animals are all in family Sciuridae, the squirrels, making groundhogs the big cousin to our hyper-abundant gray squirrels and eastern chipmunks. As with many taxonomic relationships, this one may surprise you: evolution works wonders when there are niches to fill!

Groundhogs are most famous, of course, for one of our more peculiar holidays. Groundhog Day is a national treasure and, while I don’t much subscribe to the idea of rodent-as-oracle, the holiday does hinge on a fundamental truth: groundhogs are committed hibernators, and their spring emergence should be celebrated. To be honest, I think we should have a holiday that celebrates hibernation all its own, not just its end. Many organisms engage in hibernation, and without it could not survive the New England winter: we owe a good proportion of our biological diversity to the practice. The exact mechanisms of hibernation vary across the diversity of practicing animals, but the basic premise is the same: to conserve energy, organisms suppress metabolic activity and go into a deep torpor. During this period they don’t need to eat, and heart/breath rates slow to a tiny fraction of what is “normal.” “True” hibernation, which involves an internal suppression of metabolic activity, is exclusive to warm-blooded animals (endotherms) who possess the ability. Cold-blooded animals (ectotherms), whose body temperature is regulated by the environment, can’t down-regulate on their own. However, they can go into a cold-induced coma (sometimes called brumation) that is essentially a hibernation equivalent. While ectotherms experience a direct response to the cold, hibernating endotherms generally do so due to lack of food– not a direct response to the cold, but downstream of it. In cold temperatures endotherms must eat to maintain normal metabolic activity, and when the food supply is limited hibernation is often the safer bet.

Groundhogs are what we call an obligate hibernator, as their hibernation begins and ends in an annual cycle regardless of environmental conditions. You will therefore not see groundhogs emerging on a warm winter day. This is in contrast to facultative hibernators, who switch their dormancy on and off depending on immediate conditions. The clock-like nature of groundhog emergence is part of the “lore” underpinning groundhog day, and is based on a scientific truth. That being said, groundhogs will come out shadow or no shadow: there is no “going back to sleep.” While the animals will certainly take shelter in their burrows given poor conditions, once they’re up they’re up: time to start eating! In New England, groundhogs generally don’t emerge until late March. The February 2nd emergence of Punxsutawney Phil, in Pennsylvania, is a largely manufactured event consistent with the possibility of “six more winter weeks”– but, all in good fun, I am not here to scoff. I advocate for the celebration of seasonal cycles and phenomenon, whatever they may be, and if we need to suspend disbelief for a period then so be it.

Once up and about, groundhogs feed primarily on grass and herbs. They love fresh shoots, and must find the spring greenery delicious. Not long after emerging the animals will mate, with males visiting the females in their burrows (ooh la la). The female will then raise a litter of pups all her own, nursing them until they’re big enough to crawl up to the lip of the burrow and take in the bright summer world with bleary, blinking eyes. The animals don’t venture far from their burrows, even as adults, and are generally skittish– especially when young, they make excellent prey for hawks and coyotes and so learn to fear predators early. Even when stuffing their faces with grass groundhogs appear on high alert, their movements jerky and anxious. I’m always amazed at how fast these big, chubby animals can move– watching a groundhog tear across a lawn or meadow for the safety of its burrow is like watching a small dog run. It’s really quite remarkable.

I have noted, from personal experience, that groundhogs don’t have great eyesight: they seem mainly receptive to movement. A few weeks back I was reading on a hillside and noticed a burrow entrance nearby. When I stayed completely still, the resident groundhog appeared and ventured out into the open, chewing nervously on grass only a few feet away. As far as I could tell, the animal did not notice me. But when I shifted in my seat, boom— it whipped back down its burrow in a golden-brown blur. No wonder predators of rodents are so stealthy: movement must be disguised at all cost.

Unfortunately most groundhogs today meet their end, not in the mouth of a predator, but under the wheels of a car. The grassy medians of roads and highways are excellent sources of food, but in accessing them groundhogs must often cross asphalt– not a safe place to be. While the animals remain common, for every live individual we see another lies dead on the roadside, a grisly reminder of the cost these animals pay to cohabitate with us. Once again we find ourselves confronting what it means to be a mammal in today’s world: is it really reducible to blood and fur on the side of the highway?

I wonder how we’d react to groundhogs if they were unusual, if they only persisted deep in protected areas. Would we stop in our tracks, freeze in disbelief, to watch them forage? Would we marvel at their ecological importance, their deep cultural heritage? If the answer is yes, let’s take that magic to the everyday: we can seek wild in even our most tamed open spaces. Here, on the heavily developed shores on the Long Island Sound, such a search is essential– and, as it asks us to be creative, it’s the perfect place to hone a keen eye and curious spirit.

Hopefully these posts can help you in doing so!

Til next time!

- Brendan Murtha, 2020 Seaside Center Naturalist