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L03-課文動畫(中英字幕版)(Do Animals Sleep Like You and Me)(03：06)

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Students will choose an animal and create a presentation on its sleeping habits using Padlet for collaboration.

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How Mammals Sleep

Different mammals spend different amounts of time in non-REM sleep and REM sleep. However, all mammals studied thus far do exhibit signs of REM sleep, suggesting that , just like humans do.

Mammalian sleep is often categorized as monophasic or polyphasic. describes animals who generally receive their sleep in one concentrated time period. Humans are an example of monophasic sleepers. Our circadian rhythms encourage us to sleep for extended periods at night and be active and alert during the day.

Polyphasic sleepers, on the other hand, tend to sleep in multiple periods throughout a 24-hour cycle. Polyphasic sleep is more common, as many animals need to maintain some level of vigilance against predators. However, if threats are minimized, animals can enjoy monophasic sleep. Marmosets, for example, sleep in trees surrounded by their family, enabling them to feel more protected and experience monophasic sleep.

Land Mammals

Like giraffes and elephants, horses don't sleep much, and when they do, they can sleep standing up. However, once they enter REM sleep, they lie down.

On the other end of the spectrum, there are dogs, who spend . Another 21% of their day is spent in a state of relaxed drowsiness, ready to nap at a moment's notice. Little brown bats sleep even longer, at about Some of that time is spent in a state of torpor, or hibernation.

What Is Hibernation?

Hibernation is a sleep-like state many mammals and some other types of animals engage in. During hibernation, which can last months at a time, an animal eats, moves, and produces waste very infrequently and only during brief periods of mild arousal.

There's a common misconception of hibernation as an extended sleep state, but that's not quite correct. Hibernation is more properly understood as a state of torpor. During torpor, animals have a , heart rate, body temperature, and These effects are similar to what happens during sleep, but they're more pronounced during hibernation than in normal sleep.

Animals hibernate to conserve energy during severe temperature changes or when food is scarce. Bats, for example, must decide whether to hibernate or migrate when their food supply of insects dwindles in the colder months. Some bats may stick around, conserving their energy by entering torpor for a few hours on a chilly day, or hibernating for six months until insects return in the spring.

When people think of hibernation, they frequently think of bears - although the hibernation bears experience is . During torpor, a bear's body temperature stays nearly the same, although it won't eat, drink, urinate, or defecate much for a period of up to seven months. Other animals that hibernate include the , , ground squirrels, and .

When it comes to sleep duration, walruses are like the bats of the sea, sleeping between per day. They can sleep in water and on land, although they sleep for . When walruses sleep in the water, they usually lie at the bottom, float along the surface, or lean against something while in a standing position. They can even hook their tusks onto an ice floe and sleep that way. Like elephants, walruses can go for days without sleep. They can swim for up to 84 hours before needing to recharge.

Birds also sleep unihemispherically, with one side of the brain asleep while the other stays awake. As they sleep, only the eye associated with the sleeping hemisphere of their brain is closed.

Unihemispheric sleep allows birds to protect themselves from predators. For example, mallard ducks can sleep in a row. The ducks at the end will be most likely to sleep unihemispherically, with their outward eye remaining open, while ducks in the middle sleep with both eyes closed.

Reptiles and Amphibians

Reptiles and amphibians are some of the least studied animals when it comes to sleep. Historically, REM and slow-wave sleep were thought to exclusively be sleep patterns of mammals and birds. However, emerging research indicates that reptiles such as lizards may also experience these stages of sleep, even in sleep cycles .

Like other animals, lizards choose sleep perches that maximize their safety. They may sleep on leaves, with their heads oriented towards the . Some predators, like , sleep unihemispherically so they can keep an eye out for threats and food.

While crocodiles sleep with one eye open, snakes - in fact, they must, since they don't have eyelids. Snakes may sleep for days at a time, digesting their food.

Sort of, but it's probably more appropriate to call what fish do "rest." When fish are resting, they slow down their activity level and metabolism while remaining alert enough to protect themselves from danger. They float in place, , or find themselves a safe spot in the mud, sand, or coral to rest. Parrotfish even secrete a cocoon of mucus around themselves to stay protected while they sleep.

The way a shark sleeps depends on how it breathes. sharks breathe through their cheeks, which allows them to rest motionless in a cave or on the sea bottom. Scientists have observed nurse sharks, a type of buccal pumping shark, entering a sleep-like state in which they appear sluggish and still. Their eyes are half-closed, and their pectoral and tail fins prop them up as they use a rock for a pillow.

fishes and sharks, on the other hand, ventilate their gills by keeping their mouths open while they swim. They must swim continuously, so they have to find creative ways to sleep. Scientists hypothesize that ram ventilating fishes may take advantage of currents, allowing the current to push water over their gills and enable respiration. It is more likely, however, that they sleep unihemispherically, enabling one eye to stay open and monitor their environment.

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References

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Have you ever wondered how giraffes sleep, or how fish sleep? Read about the sleep patterns of various animals, including walruses, sharks, elephants, and more.

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For advanced students, explore the relationship between an animal's environment and its sleeping patterns.

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How do animals sleep? Learn about sleeping habits of animals.

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They actually sleep for short periods of time during the day and night. Sharks stay upright and stiff while dozing, and can even sleep without closing their eyes

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they get very little energy from their diet. Eucalyptus is toxic so koala’s digestive system has to work hard to digest

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Animal sleeping Habit: Whales don’t move when they sleep.Then upright.

Why: Because it’s head too big.

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Flamingos sleep while standing on one leg with their head placed on their backs. While this position may seem strange, it is quite normal for flamingos.

Why do they sleep with one leg? By standing on one leg it helps them conserve body heat.

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Kangaroos spend 60% of their day sleeping. There is no fixed sleeping place. They usually sleep directly among the branches of trees. First they curl up and then use their buttocks and feet to support their whole body weight.

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Why:Because they are at the bottom of the food chain and are prey to almost all predators, they are naturally very alert to avoid being eaten.

Sleep habit:when they sleep, they keep their eyes open.

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Hippos have interesting sleeping habits and methods. They typically rest in water or mud, which helps keep their bodies cool and prevents skin sunburn. Hippos are primarily nocturnal, being active at night and sleeping during the day in the water. They can submerge most of their bodies while keeping their nostrils above water for breathing. Additionally, when hippos hold their breath underwater, they automatically wake up when they float to the surface, allowing them to rest safely even in deep water.

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This sea turtle will stick itself in the rocks when sleeping at night to avoid being swept away by the current, just like the sea otter in the text

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WHY 1. Save effort 2. Convenient to escape 3. Keep warm.

EFFECT

When encountering an enemy, they can quickly escape by releasing their claws.

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Sloths have a very particular sleeping posture,they hang up their feet on the tree and hang the entire body up sidedown.So why do sloths sleep in this way?The color of sloths is similar to the tree,this protective color can avoid them being attacked by predators. Hanging on trees while sleeping can also help them hide in the environment.

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Pangolins are animals that sleep during the day and are active at night. They are nocturnal. When it is time to sleep, pangolins find safe places where they can rest without being disturbed. They usually sleep in burrows, which are deep holes they dig in the ground. Sometimes, they use hollow trees or rock crevices to sleep.

Pangolins curl up into a ball when they sleep. This protects their soft belly from danger. Their hard, scaly bodies help keep them safe while they rest.

They sleep for many hours during the day and wake up at night to look for food, like ants and termites.

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Frogs