Animals hibernate in the winter to survive the cold and dark. They rely on stored energy reserves and possibly stashed food to survive the winter.
Some animals hibernate during the summer. This is called estivation or aestivation.
Hibernation and torpor are different states of inactivity and deep sleep, where the animal will wake up due to disturbance.
Hibernation refers specifically to a period of time when an animal goes into a dormant phase. There are different types of hibernation for different animals.
Some species of animal can survive without oxygen while they’re sleeping.
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Mammal:
Bat
It takes a lot of energy for bats to fly about. Thus they need to consume a lot of food, such as flies and beetles, to keep themselves fueled for their daily activities.
When winter arrives, they have to make a choice between traveling to warmer climates where there is an abundance of food or hibernating for the season.
By reducing their energy use, they preserve their resources. As a result of hibernation, metabolic, cardiac, and respiratory rates slow down, allowing the organism to survive on fat reserves.
As they enter trance, their heart rate drops from 300 beats per minute to 10 beats per minute.
Bodies reach a temperature very close to freezing but do not freeze solid.
Bear
Winter is a harsh time for animals, and hibernation in caverns and migration south are among the ways they cope.
In the traditional sense, bears cannot hibernate as other mammals do. When bears hibernate, they enter torpor, a lighter form of sleep.
During the winter, animals hibernate in order to conserve energy and protect themselves from the elements.
In hibernation, an animal’s body temperature drops, along with its breathing rate, heart rate, and metabolic rate, which indicates how much energy it uses.
Chipmunks
In hibernation, chipmunks’ heart rates drop to 4 beats per minute. The body temperature drops from 94 degrees F to 40 degrees F, depending on the burrow’s temperature.
As well as eating the food they have stored, chipmunks also pee and poop every few days during winter.
Dormouse
Dormouse sleep on the ground throughout the winter. Due to the consistency of the temperature, they need to remain cold to remain hibernating.
Hibernating on the ground keeps them moist. People often find hibernation nests in exposed areas.
Although they hibernate on the ground, research indicates they are hard to locate, which may make them more vulnerable to predator attacks.
Ground Squirrel
Ground squirrels hibernate within their cozy tunnels during the colder months of the year.
In order to hibernate, ground squirrels curl into balls and place their heads between their legs and tails on their head.
Additionally, they modify the pace of their heartbeat so that it matches their breathing. It emerges from its slumber once every seven days to feed.
Ground squirrels are more likely to emerge from their burrows and look for food on days with higher temperatures.
Hedgehog
Hedgehogs hibernate throughout the winter. While hibernating, hedgehogs enter a state of torpor, in which their body temperature is lowered to match their surroundings.
It allows them to conserve energy, but it slows down all of their other body systems, preventing them from engaging in regular activities.
Typically, they hibernate from October/November through March/April. During this period, they can move nesting sites at least once and can sometimes be seen out and about.
If the winters are mild, hedgehogs can remain active well into November and December.
Woodchuck
Woodchucks are one of the few winter hibernating animals.
Winter dens are often located in forested areas, so they put on weight during the summer in preparation for this time.
They hibernate from October to March.
During hibernation, a woodchuck’s body temperature drops to 40 degrees Fahrenheit, and its heartbeat slows to 4 beats per minute!
Yellow-bellied marmot
Their hibernation lasts approximately eight months, beginning in September and ending in April.
They construct burrows for themselves as a place of refuge and hibernate throughout the colder months in these dens.
Crustacean
Blue Crab
Blue crabs don’t like colder water in winter. Therefore they migrate. They spend the winter in deeper waters submerged in mud or sand. This isn’t hibernation but dormancy.
Hermit Crab
Hermit crabs hibernate when the temperature drops below 68 degrees Fahrenheit (20 degrees Celsius).
The hermit crab lives in tropical climates. Their bodies can’t create warmth on their own, so they have to draw warmth from their environment.
Diamondback Terrapin
In the colder months, diamondback terrapins hibernate in the muck at the bottom of tidal creeks, where they remain motionless and submerged.
Amphibian:
Frogs and Toads
Terrestrial frogs hibernate on land in burrows that are often 50cm to 60cm deep. This helps when it gets colder and puts them below the frost line.
Some frogs, like the wood frog, aren’t good at digging, so they look for deep gaps in logs or rocks or burrow as far as they can in dead leaves.
Reptile:
Crocodile and Alligators
Alligators do not hibernate in winter. Below 55°F, they enter a lethargic state called brumation.
Alligators remain aware of their surroundings during this state. In order to avoid dehydration, alligators slow down their metabolic rate and do not eat during this period.
Common Box Turtle
When food is scarce, and temperatures are low, brumation allows turtles to survive. The turtle burrows into soft soil and enters a state of inactivity and torpor.
Winter is a difficult time for turtles due to food shortages and low temperatures. Brumation is also known as hibernation in reptiles.
Snake
In the United States, snakes sleep during brumation.
Weather patterns determine when snakes brumate, but it usually occurs from September to December and can last until April.
If the weather changes and starts warming their blood and this makes them more active. Snakes are likely to notice when the weather changes once they leave their dens.
Worm:
Earthworm
Earthworms dig down as much as 6 feet before the ground freezes during winter. As they hibernate, they form a slime-coated ball.
They survive for lengthy periods without moisture due to their mucous covering.
Fish:
Lungfish
During the winter months, the lungfish digs 1-9 inches into the soil in its waterway. By wriggling in the mud, it creates a bulb-shaped chamber where it rests.
The lungfish estivate until enough rain falls to allow them to swim again. The cocoon they dig traps moisture and lets in the air during the fish’s evaporation.
A lungfish can survive years beneath a dry landscape because of burrowing, mucus cocoons, and self-digesting.
Gastropod:
Snail
Because snails need moisture to survive, they can sleep for up to three years if the weather’s bad. Snails usually hibernate in colder regions. They seal their shells and then slow their heart rate. This helps them sleep through icy weather.
In warmer climates, snails do not hibernate.
Bird:
Poorwill
In the winter season, they enter into a torpidity state in which the body’s temperature, heartbeat, and breathing rate are lowered.
They are the only bird known to do this. This period can last weeks or even months.
The species spends much of the winter inactive, concealed in piles of rocks, on the southern edge of its range in the United States.
List of Insects that Hibernate
Butterflies and Months
Insects don’t hibernate. Instead, they go into a state of dormancy. Butterfly larvae (caterpillars) hibernate most often, followed by pupae (chrysalises), eggs, and adults.
They find hollow trees, log piles, and old rabbit holes to rest for the winter. They will even find rest in sheds, garages, and attics.
Ladybird
During the winter, ladybirds hibernate.
As adults, they hibernate through the winter. Different species find different places to hibernate.
They find places like under tree bark, while others sleep under leaf litter, etc.
Bumble Bees
The queen bee hibernates during winter. They make small holes beneath or on the ground’s surface.
Upon emerging from the ground in spring, they begin to lay eggs in order to establish a new colony.
