<f autumn’s progression towards winter are all around. Apples hang heavy and ripe from the trees, birds flock together and prepare to fly south, students break out coats and scarves, and Northfield even experienced an early dusting of snow, hinting at what’s in store for winter term. It is this kind of weather that makes many Carleton students yearn to hide in their dorm rooms, away from the frosty air. And though unfortunately hibernation is not an option for students, it is the natural thing to do this time of year for an often overlooked animal in the Arboretum: the snake.
Garter snakes as well as redbelly snakes both call the Arboretum home. Garter snakes are one of Minnesota’s most common snake varieties and inhabit both rural and suburban areas, often around ponds. Identified by their black color with characteristic lengthwise yellow stripes, garter snakes will reach about two feet in length at adult size. Because they often feed on mice (along with similarly-sized rodents, small amphibians, worms and insects), garter snakes play a vital role in keeping the mouse population in check. In turn, these snakes become food for other Arboretum animals, such as hawks, owls, foxes and ground squirrels. During this time of year as the weather cools, garter snakes seek refuge below the frost line to hibernate. Garter snakes will use rock crevices, ant mounds, or burrows dug by other animals as their hibernation haven—their “hibernaculum.” Year after year, the snakes will return to the same hibernaculum as temperatures drop in autumn.
Redbelly snakes, similarly, winter in ant mounds or rock crevices. The smallest Minnesota snake, they mature to be about seven to ten inches in length and feed on insects and invertebrates. Like the garter snake, the redbelly snake most often resides near water and is often preyed upon by large birds such as owls or hawks. Though they come in two color variations, both varieties can be easily identified as redbelly snakes by their dark-colored bodies and their red undersides.
The next time you’re walking through the Arboretum, especially near water, take a close look at the ground and you might just find a snake hibernaculum. Often unnoticed even by frequent Arboretum visitors, the winter abodes of Arboretum snakes from the outside seem little more than cracks in rock or holes in the ground. However, despite its homely exterior, the hibernaculum is essential for the survival of snakes from one year to the next—braving that frigid Minnesota winter we all know is knocking at the door!
Neither the garter snake nor the redbelly snake is poisonous, so if you happen to encounter one, take a minute to admire these hidden wonders of the Arb.