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Hibernation

Painted Turtles Basking

5-1-19 painted turtle_U1A7417Water temperature of fifty-nine degrees Fahrenheit is the magic number for Painted Turtles in the fall. Below it, their metabolism slows to a near standstill – their heartbeat slows to only one beat every few minutes and they do not breathe through their lungs (if conditions allow, they may absorb oxygen dissolved in the water through specialized skin cells near the tail). Their body temperature averages 43°F. when hibernating in the mud at the bottom of ponds. Occasionally a Painted Turtle is seen swimming under the ice, but for the most part, hibernation rules from October to April in northern New England.

When the water reaches 59°F.- 64°F. in the spring, Painted Turtles become active again. In addition to foraging, they immediately start basking in the sun. Being cold-blooded, or ectothermic, they need this external source of heat to warm their body, but the UV light also regulates their metabolism and breeding as well as helps produce Vitamin D3, which is essential for the health of their bones as well as their internal organs.

Basking can also help relieve aquatic turtles of ectoparasites. Leeches are a blood-sucking ectoparasite that can cause anemia in reptiles. Drying out in the sun causes the leeches to shrivel up and die. Algae on basking aquatic turtles can also dry out and fall off, allowing the shells to retain their aerodynamic nature.

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Time To Take Down Bird Feeders !

3-25-19 black bears 1214Black Bears have just started to emerge from hibernation in northern New England, and their appetite is fierce. Male black bears will typically drop between 15 and 30 percent of their body weight, while reproductive sows can lose up to 40 percent of their weight over the winter. Although omnivores, a black bear’s diet consists of 85 percent plant material, especially in the spring and summer. At this time of year bears favor the tender emerging shoots of sedge and grasses, willow catkins, leaf buds and skunk cabbage. However, these plants are not always available to them when they first become active. Being opportunists, if bears can’t find natural food sources, they go looking for alternatives, such as those provided by humans.

Sunflower seeds are a Black Bear’s dream come true, nutritionally speaking. A bird feeder full of them replaces hours of foraging in the wild. With an outstanding sense of smell (many times greater than a bloodhound’s), Black Bears will find and raid feeders at this time of year when there is a lack of other food sources. Therefore, if you wish to avoid creating a “nuisance” bear, it is advisable to take down your feeders by April 1st. Black Bears have excellent memories, particularly regarding food sources. They will return time after time, and may resort to unwanted (by humans) behavior in order to get more of the food that was at one time available. Once this occurs, their well-being is jeopardized.

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Male Woodchucks Out and About

2-22-19 woodchuck burrow IMG_0555Hibernation, the true slowing down of one’s metabolism (a Woodchuck’s body temperature drops from 99 degrees F. to 40 degrees F. and its heartbeat drops from 100 beats per minute to 4 beats per minute) is one way an animal conserves energy. Male and female Woodchucks use the energy they’ve conserved very differently in early spring.

At the end of February and in March, males arouse themselves about a month prior to the mating season and spend long periods visiting females and defending their territory. Muddy tracks and trails can be seen near their winter burrows (see photo) at this time of year. Females remain in their burrows in a state of hibernation, saving as much energy as possible for the birth and raising of their young. After confirming the presence of females on their territories, males return to their burrows for the next month or so, awakening along with the females in time for their mating season.

The timing of Woodchuck procreation is not a relaxed affair. It is quite precise, in fact, for very good reasons. If Woodchucks mate too early in the spring, their young won’t be able to find food once they are weaned. If they mate too late, their young won’t have the time necessary for putting on weight and storing fat before hibernation begins. Now is the time to look for signs indicating male Woodchuck activity near their winter woodland burrows.

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Fermenting Apples & Black Bears ≠ Inebriation

11-5-18 bear scat MH_20091011_233455_4If you investigate the contents of Black Bear scat this time of year, you may well find nothing but chunks of digested and semi-digested apple (pictured).  For several weeks before hibernation begins bears spend their days and nights foraging for food that will sustain them through the coming months (“hyperphagia”).  Fermenting apples lying on the ground are accessible and very popular with bears; hence, many scats contain them.

There have been anecdotal reports over the years of Black Bears stumbling around as if inebriated, and it is often assumed that this behavior is the result of their having consumed fermenting fruit, such as apples.  Waxwings, robins and other species of birds are known to get drunk (and even die) from fermented crab apples, mountain ash and blackberries, but it’s highly unlikely that bears follow suit.

For one thing, the pH of a bear’s stomach is around 3.5 – slightly more acidic than yeast can tolerate. In addition, the time it takes for a Black Bear to digest food is typically far less time than yeast would need to convert sugar into alcohol. Lastly, size would play a large role in an animal’s ability to become intoxicated. It would take hundreds of apples consumed at their peak level of fermentation to make even a small, young Black Bear even slightly tipsy.

If you see a Black Bear stumbling and acting strange it may well be because it is sleepy or perhaps sick, but probably not drunk. However, until researchers test the blood alcohol level of a bear that’s exhibited this behavior, no–one can say for sure what caused it.

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Black Bears Emerging From Hibernation

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A year ago, in April 2017, while following Black Bear tracks in New Hampshire, I had the good fortune to encounter the bears themselves. Because Black Bears have started coming out of hibernation (April is when most do so) I felt it was timely to share some of my photographs and observations of that encounter. (I did not do so a year ago for fear of bringing attention to and thereby disturbing these bears.)  As I followed the bear tracks, I eventually came upon a refuge, or “babysitter,” tree – where bears rest and cubs/yearlings take refuge when their mother goes off foraging or when she senses danger. I had read about such trees, but never discovered one myself. It was very recognizable — a very large White Pine surrounded on the ground by bear scat and gnawed saplings – fresh signs that bears frequented this area. At the base of the tree were several large “bowls” or indentations in the pine needles that looked as if large animals might have bedded down repeatedly in them, forming nests.

I continued tracking, eventually turning around to head back to where I entered the woods. On my return I passed by the babysitter tree again. To my utter delight I discovered a mother bear with her three yearlings fast asleep in the beds at the base of the tree. It was snowing lightly, and I surmised that this family had recently emerged from their deep winter’s sleep and was still a bit groggy. (Adult males are the first to emerge; females with cubs are the last.) While the yearlings slept on, the mother opened her eyes and decided to tolerate my presence for the next couple of hours. In Naturally Curious posts this week and next, I will share this once-in-a-lifetime experience with you as well as the behavioral observations I made.

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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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Black Bears Foraging

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This is the time of year when Black Bears are looking for every available source of food in order to bulk up before entering hibernation. During this period of gorging (hyperphagia) Black Bears consume large quantities of fruits, berries, nuts, grasses, roots and insects.

In particular, they favor the brood (larvae and pupae) of ants, due to their relatively high content of fat and protein. Black Bears find brood by detecting the pheromones and other chemicals such as formic acid that ants use for communication and defense. Research has confirmed that Black Bears will dig up as many as 200 ant colonies a day, flipping rocks, moss and leaf litter over and tearing apart logs, stumps and snags (such as the one pictured), using their canine teeth and claws to gain access to the ants. Once they have torn apart the stump or snag, they use their long, sticky tongues to gather brood. Anthills are avoided except for when Black Bears are extremely hungry, due to the fact that bears prefer not to get a lot of soil or sand mixed in with the brood they’re eating. (Thanks to Virginia Barlow for photo op.)