How much do you know about hibernation?

sleeping bear
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When things get tough, some animals head to bed. They hit the hay for weeks or months, emerging when the environment is a much more agreeable place. Bears are the animal most known for hibernating, but they aren't the only ones. Test your knowledge on this fascinating survival technique.

Question 1 of 12

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Why do animals hibernate?

Hibernation is a way to conserve energy. Often animals do it because of extreme temperatures. They may also hibernate when food is scarce. Some studies suggest that animals hibernate to avoid detection by predators.

Question 2 of 12

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Hibernation is exclusive to cold-weather animals.

Although hibernation is often seen as a way to beat plummeting temperatures, there are also tropical creatures who do it to beat the heat.

Question 3 of 12

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Which are more likely to hibernate?

Animals often have the choice of hibernating or migrating to some place warmer. Smaller animals are more likely to hibernate, because migrating would require so much energy in relation to their size. Larger animals are less likely to hibernate because of all the energy needed to warm up large bodies.

Question 4 of 12

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What is the only primate known to regularly hibernate?

Madagascar's dwarf lemur is the only primate known to hibernate on a regular schedule. The animal hibernates in holes of trees for up to seven months each year. Scientists found that the primate is also the only animal known to fully fall asleep while hibernating in its natural environment.

Question 5 of 12

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It's nearly impossible to wake an animal while it's hibernating.

Some hibernators, like the American black bear, can be aroused relatively easily. However, most small mammals fall into a deeper state of suspended animation. It’s very hard to wake those animals while they’re hibernating.

Question 6 of 12

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What saves hibernating frogs from freezing?

During hibernation, ice crystals can form in a frog’s bladder or under its skin. But a high concentration of glucose in its body keeps major organs from freezing. Even if a frog’s heart stops beating and the frog stops breathing, once warmer temperatures come, the frog will thaw and “come back to life.”

Question 7 of 12

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Bears can have healthy pregnancies during hibernation.

Pregnant bears will rouse themselves just long enough to deliver their cubs, then go back to hibernating. Cubs will snuggle and nurse while their mothers slumber.

Question 8 of 12

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When an animal enters a hibernation-like state in hot or dry periods, it's called:

When it’s very hot or very dry, some terrestrial and aquatic animals will dive into a prolonged, dormant state called estivation. Brumation is a hibernation-like state in reptiles. Torpor is a short-term state where an animal’s normal metabolism is depressed to less than 5 percent of normal. Hibernation is an extended form of torpor.

Question 9 of 12

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Animals always store food for hibernation.

Some animals will stock up on non-perishable food and keep it around them while they hibernate. But then they have to wake up briefly in order to eat. Other animals will just eat a ton before they hibernate, starting usually in late summer if they hibernate in winter. Other animals will do both: eat a lot before they hibernate and still stock up for meals during brief wake-up periods.

Question 10 of 12

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Once animals start hibernating, they don't wake up until they're done.

Animals don’t stay in their comatose state the entire time. They have to periodically wake themselves and warm up. Some researchers think that ironically, they need to wake up in order to sleep. Others think waking up triggers their immune systems to fight disease. About 80 percent of their energy is spent waking and warming up.

Question 11 of 12

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snail hibernating
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What helps snails hibernate?

Not all snails hibernate, but those that do are usually avoiding either extreme hot or cold. They typically cover themselves in a thin mucus, which protects them from the elements and keeps them from drying out.

Question 12 of 12

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Do zoo animals hibernate?

Zoo animals often have warm environments and plenty of food, so they don’t typically have the same cues that would trigger their instinct to hibernate. However, some zoos intentionally prompt hibernation in some animals in order to make sure their lives are more natural.

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sleeping bear
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