Tag Archives: hibernation

10 Things You May Not Know about Today’s Famous Animal (The Groundhog)

woodchuck-0153Happy Groundhog Day! Many people know it’s Groundhog Day because the news channels always seem to do some odd piece on it, often showing a groundhog that they get from …? who knows where they get this groundhog but it probably isn’t one that was hibernating in the first place. Legend has it that if a groundhog sees his shadow we are in for 6 more weeks of winter. If the day however is cloudy and the groundhog doesn’t see his shadow, we can take this as a sign of an early spring.

So we know there is a day dedicated to Groundhogs, but do we know anything at all about the actual animal responsible for this day? The Groundhog?

Here are a few facts about groundhogs:

1. First off, another name for the Groundhog is Woodchuck. In the Naturalist community of nature centers that I was part of for many years, the mammal seems to be called a woodchuck more than it was called a groundhog. But on TV, the reverse is true. Whatever name you use, it’s the same animal–a mammal and member of the rodent family and thus relatives with mice, squirrels, porcupines and beavers.

woodchuck-01402. Groundhogs are mammals and one of the few mammals who are what is referred to as “true hibernators.” The things they are capable of doing are nothing short of astonishing!

3. For instance, during hibernation the body temperature of a woodchuck may drop 99 degrees to as low as 37 degrees. To give you some perspective, if a person’s body temperature drops as little as 3 degrees, s/he can go into mild hypothermia.

4. A woodchuck’s heart rate slows from 80 beats per minute to just 5.

5. During hibernation, the breathing of a woodchuck drops from 16 breathes per minute to as few as 2. They don’t eat during this entire time–up to 3 months, but incredibly, will not lose more than 1/4th of their body weight due to their slower metabolism.

6. As rodents, a characteristic is that they have incisors that continually grow and are a shade of orange. The incisors of a woodchuck can grow 1/16th of an INCH EACH WEEK, except when they are sleeping away the winter.

woodchuck-0037. Groundhogs are excellent diggers, capable of excavating amazing homes in the hard ground. Their burrows can be as long as 30 feet and up to 5 feet deep. These underground homes have multiple entrances and multiple chambers within, for different purposes. For instance, there is a spot for sleeping and giving birth (for females) as well as a separate toilet area.

8. Groundhogs  eat a variety of plant material, making them herbivores, but none of this is wood, as their name woodchuck seems to suggest. Instead, they feast on succulent plants, fruit, buds, leaves, clover, and, as most gardeners can tell you, lots of garden veggies! I once watched a family of woodchucks in a yard filled with dandelions, devouring the yellow flower heads as if they were candy.

9. Females give birth in the underground burrow, in the spring, to between 2 and 6 blind, naked and helpless babies. The young are weaned and on their own by 5-6 weeks of age.

10. When alarmed, groundhogs will emit a shrill whistle, earning them the nickname of “whistle pig.”

Bonus: Groundhogs can climb up a tree or swim across a body of water if need be, but they are not very fast runners–reaching a top speed of 8 mph. When confronted with a predator like a fox, coyote or bobcat, they will almost always run for the safety of their underground burrow…


Groundhog meets Bobcat

Once, I was watching a family of woodchucks in my yard when a bobcat wandered in. The female woodchuck sent the little ones scurrying but did not make it to its burrow in time and came face to face with the bobcat. What do you think happened?  If you want to hear the rest of the story and learn what happened,CLICK HERE.


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Weekly Puzzler Answer #38


Many birds migrate for the winter, traveling to places where food will be more readily available. They do not migrate simply to escape the cold temperatures as feathers provide sufficient warmth to endure the frigid air. But in many parts of the Untied States, winter means not very many insects and birds that feed primarily on insects need to go elsewhere.

A bird called a Common Poorwill however DOES eat insects and does NOT migrate.  Instead, it hibernates, entering a state of what’s called “torpor” during which it slows down its metabolism and drops its temperature –to as low as 41 degrees– to basically sleep for days or even weeks at a time. During torpor their respiration is reduced up to 90%! Common Poorwills are said to be the only bird that hibernates.

Unknown-2The Common Poorwill is in the Nightjar family and is common throughout the western United States. Like other birds in its family, it has AMAZING camouflage, able to blend into its surroundings so perfectly that few people ever get to see one, unless it’s a quick glimpse of one in the headlights on a road after dark. In fact, this is the first puzzler that I have ever done that I could not supply my own photo–these photos are from Wikipedia.

Common Poorwills are 7.5 -8.3 inches long, weigh just under 2 ounces and have tiny feet and a tiny bill. They spend much of their time on the ground, sleeping during the day and hunting during the night. They hunt insects from a perch on the ground.

Resources, including more pictures of this bird:

Cornell Lab of Ornithology




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Winter World Quiz Answers

The natural world with all of its plants and animals is amazingly complex, with each species having so many adaptations that allow it to perfectly fit into its environment. It is difficult to know all the different ways animals survive winter. Here is a small sample, giving information about a handful of our native animals.

Let’s see how you did on the Winter World Quiz. Here are the answers:

045_21. Bears, chipmunks and woodchucks are true hibernators. FALSE. Chipmunks and Woodchucks are true hibernators but bears don’t fit the definition of a true hibernator. That’s because true hibernators have a drastic drop in body temperature, respiration and heart rates and they are difficult to wake up. For example, during hibernation, a woodchuck may have a body temperature of 38 degrees F compared to 98 degrees the rest of the year. Their heart rate drops from 80-105 down to only 4 or 5 beats per minute! A bear on the other hand only lower their body temperate a few degrees and breath a little slower than during the rest of the year.  A bear wakes easily while it is sleeping and doesn’t have the dramatic drop off in heart rate or temperature. They are amazing though, as they can sleep for more than 100 days! If you want to read more about BEARS, click Here.

Woodchucks (groundhogs) are true hibernators.

Woodchucks (groundhogs) are true hibernators.

2.  Woodchucks and Groundhogs are the same animal.  TRUE. Many people don’t know this, but it is true. In my experience it seems like Naturalists and Biologists call the animal a woodchuck but other people, for instance those on the TV reporting about “Groundhog Day,”  call it a groundhog. Either way, it’s the same animal–a mammal –a rodent–who spends the winter hibernating.

Some birds migrate to other places to escape the cold temperatures.     FALSE. Some birds DO migrate, or fly to another area to spend the winter, but it’s not because of the cold temperatures, it’s because they can’t find food. Have you ever worn a down jacket or slept beneath a down comforter? Then you know feathers are very warm! Birds can tolerate the cold, they just are unable to find the foods they eat when the ground is frozen or covered in snow. Birds that eat insects must migrate where insects will be available.

A common GARTER snake. (Not a garden snake as some people call it!)

A common GARTER snake.

Reptiles and Amphibians spend the winter in a state of dormancy.  TRUE. Both groups of animals have amazing adaptations that allow them to sleep for the entire winter. Many, like garter snakes and black rat snakes, congregate in large numbers in a place referred to as a hibernaculum. This is a place, perhaps a cave or mine or underground hollow, that they might have been going to for MANY, MANY years. In the case of others, like wood frogs, they might burrow beneath some leaves, freezing solid for the winter. They survive because of a chemical like antifreeze that is in their bodies that prevents ice from forming within their cells. Some turtles burrow down in the mud at the bottom of the pond, while others spend the winter sleeping on land, perhaps under a fallen tree or pile of rocks.

frog-51465. There are no active insects during winter.   FALSE. Honey bees –the workers and the queen–do not die before winter and stay active within their hives. (The drones do die before winter) Honey bees are able to accomplish this feat by beating their wings rapidly to keep the hive at a constant temperature of around 40 degrees. They sustain themselves on the honey that they have stored up before winter arrives.

6. Because it’s so cold in the water, beavers and otters must hibernate.  FALSE. Beavers, otters, mink, and muskrats–all animals that live in an aquatic environment, do not hibernate. Instead, they put on a layer of fat, get a thicker coat and stay active during winter. Beavers will store up a food cache outside of their lodge that they will feast on if their body of water is frozen over.fox-2

7. Most insects overwinter in the larval formFALSE. Some insects overwinter in the larval form–take a wooly bear caterpillar for instance– but most overwinter in the egg or pupa stage. The pupa stage is the stage just before becoming an adult and may last for months. As an example, a caterpillar that becomes a butterfly may overwinter in the chrysalis stage, which is just another word for the pupa  stage. Many overwinter as eggs, left behind in the fall by the females.fox-0245

8. Some bats hibernate, some migrate and some do both.  TRUE. Depending on where they live, a bat in the United States may hibernate, migrate or migrate and then hibernate! It all depends on where they live. But our bats are insect eaters so during winter when insects are not around, the bats must do something to adapt to this change. They might migrate to a cave and gather with hundreds and even thousands of other bats, or they may just hibernate where they live. In recent years, bats are really in trouble as thousands of them are dying during hibernation. If you want to read more about this, click HERE.fox-0002

fox-0669. Fox, coyotes and bobcats stay active.  TRUE. All three of these animals stay active during winter, along with deer, squirrels, raccoons and many kinds of birds. Their diet is likely to change and they get a thicker fur coat, but they do not have the luxury of sleeping like a bear for the entire winter!

10. Some animals, like a deer, change the color of their fur during winter. TRUE. The change in the color of a deer’s fur may not be obvious to everyone, but it is more muted in the winter to blend in with the winter landscape. Weasels and rabbits have a white fur coat during the winter that allows them to blend into the landscape and avoid detection from predators.

Can you find the deer?

Can you find the deer?

How did you do? I hope this was a fun way to learn about some of our animals and I hope you come back and visit again soon. Happy wildlife watching!


Winter World by Bernd Heinrich

Bee colonies 

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Weekly Puzzler Answer #37

chipmunk-0025Chipmunks are what are referred to by biologists as “true hibernators.” Many animals take long naps for the winter but only a handful actually hibernate.

Woodchucks (groundhogs) are true hibernators.

Woodchucks (groundhogs) are true hibernators.

Chipmunks, woodchucks, ground squirrels, jumping mice and bats are on the list of true hibernators. During hibernation they are very hard to wake up. Their heart rate, respiration and body temperature drop dramatically. In contrast, animals that aren’t true hibernators–like bears, raccoons and skunks, wake easily and don’t have such dramatic drops in temperature and heart rates. For example, a sleeping bear’s temperature only decreases by about ten degrees and they breathe only a few breaths slower. Interestingly, bears can go more than 100 days without eating, drinking or passing waste and females actually give birth during their winter sleep! Imagine waking up after a long nap to find a baby snuggled by your side!

During winter a chipmunk’s heart rate drops from 350 to only 4 or 5 times per minute. Their body temperature goes from 96-104 all the way down to 42-45 degrees F during winter. And while they might take 60 breaths per minute during the rest of the year, during hibernation, this drops to fewer than 20. If you discovered one, it would likely be curled up in a tight ball and looking for all intents and purposes, dead.

In the winter during periods of no snow or warm temperatures, chipmunks might rouse from their sleep and emerge from their dens, especially if the fall produced a good harvest of nuts. 045_2Chipmunks are notorious for filling their cheeks full of nuts, seeds, berries and grains. They take these back to their underground burrows–which may be as long as ten feet–and deposit them in special food chambers. These may contain hundreds of nuts by the time winter arrives. They also have separate tunnels for their “toilet.”

Like chipmunks, ground squirrels also hibernate.

Golden-mantled ground squirrels, like chipmunks, also hibernate.

Chipmunks are the smallest members of the squirrel family, weighing in at 1-5 ounces. During hibernation their weight may drop by half! Many don’t make it through the winter because their fat reserves run out or they are found by predators, like a fox or coyote and don’t wake up before they are eaten.

Chipmunks, like the golden-mantled ground squirrel, excavate burrows in the ground unlike other squirrels like red, gray and flying squirrels that make their homes in treetops or in hollow cavities in trees. On average a chipmunk in the wild lives only 2-3 years.

To read more about bats and some of the troubles that they are having lately while they hibernate, click HERE, or about gray squirrels and how they spend their winters, click HERE. For this week’s puzzler, Click HERE.


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Weekly Puzzler #38

cardinal-The falling snow in this picture makes it obvious that this male cardinal does not spend the winter hibernating. Are there any BIRDS that DO survive winter by hibernating? CLICK HERE for the answer.

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Weekly Puzzler Answer #35

bucks-3132If you feed the birds in the winter, you will know the answer to last week’s puzzler: Gray squirrels STAY ACTIVE during the winter!

If the weather is harsh and snowy for a long time, they might hole up–often with other squirrels– in their leaf nest high in the treetops, or in their cozy hollow in a dead tree, but they do not sleep through the winter like some other animals.

Squirrel tracks in the snow

Squirrel tracks in the snow

Instead, leading up to the fall and winter, they grow a thicker fur coat and collect nuts like hickory, oak, beech, walnuts, that they hide in their territory, burying them in the ground, stashing them in hollows in trees.

A squirrel nest high in the tree

A squirrel nest high in the tree

Of course they can’t remember all the nuts that they buried so many forgotten ones become new trees, which of course, is a good thing for the continuation of the forest.

Click HERE for next week’s Weekly Puzzler.

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Weekly Puzzler #36

bucks-While I’m on the topic of how animals survive winter (Weekly Puzzler #35) let’s talk about another animal and how it makes it through the winter: The insect-eating bat.

As you may or may not know, many species of bats that live in the United States spend their winters hibernating, sometimes with large numbers of other bats.

Here is this week’s puzzler: Why are so many bats dying before the winter ends?

What is causing entire bat colonies to die during hibernation? And then, why should we care?

To learn the answer to this week’s puzzler, click HERE.

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