An online resource based on the award-winning nature guide

Rodents

Beavers Eating & Grooming

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This photograph conveys the essence of a beaver’s summer – eating and grooming… more eating, more grooming. During the summer months, beavers feed on non-woody vegetation (grasses, ferns, aquatic plants, etc.) 90% or more of the time. (During March/April and October/November, their diet switches to 60%-90% tree bark, and during the winter, bark from trees stored under water composes 100% of their diet.)

When beavers are not eating, much of their time during the warmer months is spent grooming, both themselves as well as each other.  Combing debris out of their coat (with the help of a split nail on both hind feet) and applying oily material from their anal glands to waterproof their fur consume much of their waking hours, both at night as well as at both ends of the day. (Castoreum, produced in castor sacs, differs from anal gland secretion, and is used primarily to mark territory.) (Thanks to Roger and Eleanor Shepard, and Sara and Warren Demont for photo op.)

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Happy Groundhog Day !

2-2-18 woodchuck IMG_2381The Woodchuck, or Groundhog, is one lucky creature, considering past practices. The observation of “Groundhog Day” originated in the mid-1800’s, and by the late 1800’s and early 1900’s the celebration consisted of feasting on this rodent. A formalized hunt took place and participants then dined on Groundhog (which purportedly tastes like a cross between chicken and pork) and drank Groundhog punch. Since then, the Groundhog has evolved into a forecaster of weather, rather than a meal.

While New England Woodchucks are curled up in their hibernacula,  Punxsutawney Phil is busy seeing if he can see his shadow today (in which case we’re in for six more weeks of winter) or whether cloudy skies will prevent that from happening and spring is right around the corner. I’d bet on the former.

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What Goes On Beneath Our Feet In Winter

Alfred's mouse2 2018-01-16 20.39.08 (003)It’s fairly unusual to see Deer or White-footed Mice, especially in the winter – they are nocturnal and they spend much of their time in the airspace under the snow next to the ground known as the subnivean layer. (A blanket of snow traps the earth’s heat, which melts the bottom of the snow, creating this layer of space.) Here both Deer Mice and White-footed Mice travel extensively, protected from both the cold (it stays within a degree or two of 32 F. regardless of outside temperature) and the eyes of predators. On cold winter days, groups including both species of mice keep warm by huddling in a common nest. (Photo of White-footed/Deer Mouse – extremely difficult to tell the difference by sight – by Alfred Balch.)

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Porcupine Trails

1-12-18 mystery photo 049A2042Porcupines are forced to exert a lot of effort if they are in need of food and the snow is deep. Unlike many rodents that are light enough to travel on top of the snow, Porcupines must plow their way through it. Their weight, short legs, and bare footpads make traveling in snow challenging, to say the least.

If the snow is deep, the winter ranges of Porcupines are considerably smaller (18 acres in one research study) than their summer ranges (160 acres in same study).  Because of the energy needed to travel through the snow, Porcupines usually feed just a short distance from their winter dens, more often than not within 200 feet. Their feeding trails from rocky or hollow tree dens to their woody food sources (often Eastern Hemlock-note bits of branches on snow in photo, American Beech and Sugar Maple), are very distinctive. They are used every night when Porcupines leave their dens to feed and again several hours later when they return.  These trails become well marked with urine, and less frequently with scat and quills. (Photo insert: Porcupine rock den entrance)

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Beavers Breaking Ice

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We’re right on the verge of when beavers will no longer be able to smell fresh air, see the sun and obtain fresh bark. Until the temperature drops to around 16 degrees F. they continue to break through the thin ice covering their pond. Once the temperature remains in the teens or lower for several days, they no longer try to break through the ice and are sealed under it until spring, unless there’s a mid-winter thaw.

Once beavers are confined by the ice, their activities outside the lodge are minimal. Beavers leave their lodge in winter primarily for three reasons: 1) to swim out to their winter food supply pile and retrieve a branch which they bring back into the lodge to eat, 2) to defecate in the water, and 3) to mate in January or February. Other than these excursions, they spend most of their days in the dark, enduring life in a lodge that has a temperature of about 34 degrees F. (Thanks to Kay and Peter Shumway for photo op.)


Beavers Preparing For Winter

9-12-17 beaver2 20160905_5707The lazy, hazy days of summer are dwindling, and beavers’ internal clocks are telling them it’s time to batten down the hatches and prepare for several months of life below the ice. This entails adding a significant amount of mud to the outside of their lodge. The mud freezes and creates an impenetrable barrier between them and predators such as coyotes that, thanks to ponds being frozen, will have access to beaver lodges. This mud is anchored by the addition of debarked branches and logs that have provided the beavers with meals of cambium during the summer.

A beaver can transport its own weight in material (roughly 45-60 pounds). Retrieving debarked pieces of wood in many cases involves carrying them over both land and water, using only jaws and sometimes a shoulder for support.  A beaver’s short, muscular neck and its powerful lower jaw muscles make this possible. Try lifting one of the larger logs on a lodge or beaver dam sometime. Then imagine carrying it any distance in your mouth with no assistance from your hands. (This feat rivals that of a moose carrying two 25 – 30 pound antlers around for several months.) While there are recorded cases of beavers felling trees 150 feet tall and 5 feet in diameter, logs of this size are not used as building material for dams and lodges, but rather the bark and upper branches provide them with food.  (Thanks to Roger and Eleanor Shepard and Sara and Warren Demont for photo op.)


The Varied Diet of Muskrats

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Muskrats are primarily herbivorous. The majority of their diet consists of the tubers, roots, stems, leaves and fruit of a variety of aquatic and terrestrial plants, particularly those of bulrush, cattail and arrowhead. A diet of high fiber is possible because of bacterial fermentation which takes place in their intestines. The digestion of many herbivores is aided by bacteria, but many plant-eaters are restricted in what they can eat because they are unable to change their diet without killing the bacteria. Muskrats, however, can and do consume large amounts of meat (frogs, fish, turtles, crayfish, etc.) and still maintain a healthy population of fiber-digesting bacteria. (Thanks to Jeannie Killam for photo op.)