動物奇葩睡眠習慣：海獺睡覺手牽手

From sleeping standing up to shutting down half of their brain, animals have some strange sleeping habits.
動物們有一些奇特的睡覺習慣，有的站着睡覺，有的一半大腦休息。

Now some of these more unusual habits, from napping giraffes to birds that sleep while flying, have been revealed in an infographic.
現在一些更不尋常的睡覺習慣已經用信息圖表展示出來了，從打瞌睡的長頸鹿到邊飛邊睡的鳥類都有記錄。

The chart maps the liveliest to the idlest creatures to reveal that Little brown bats are most lethargic, sleeping for around 19.5 hours a day.
圖表展示了從最活潑的動物到最懶惰的動物，其中小型棕蝙蝠是最嗜睡的，一天大概睡19.5小時。

This long period of sleep is thought to be a way of conserving energy and means they only hunt for a few hours each night when their insect prey are available.
這樣長時間的睡眠被認爲能夠保存能量，這意味着每天晚上它們只有幾個小時在捕捉昆蟲。

In contrast, giraffes can go weeks without sleep and when they do grab some shut eye, it’s never for more than five minutes.
相比之下，長頸鹿可以幾個星期不睡覺，它們真正閉上眼睛的時間也不會超過5分鐘。

This is because being large and slow moving giraffes are constantly vulnerable to attacks from predators, and therefore can’t sleep for long periods.
長頸鹿因爲體積大，移動不方便，所以容易受到食肉動物的攻擊，因此睡眠時間不長。

Adult giraffes sleep standing up in short bursts, but keep watch on their young which lie down to sleep, tucking their long legs underneath their bodies and curling up like a cat.
成年長頸鹿站着小睡時也會照看躺下睡覺的幼崽。幼崽把長腿彎曲在身子下面，像貓一樣縮成一團。

However, other animals are experts at multitasking and can swim or fly while sleeping.
還有其他一些動物擅長同時進行多項活動，邊遊邊睡或者邊飛邊睡。

As well as exotic beasts, the chart features pets such as domestic cats (shown above) which sleep for approximately two thirds of their lives and take extra naps when it's raining or if they're bored
除了一些奇異的野獸，圖表也突出展示了一些寵物，例如家貓，它們一生中大約三分之二的時間都在睡覺，下雨或者無聊的時候也會睡一小覺。

For example, dolphins and whales sleep while keeping half of their brain alert, so they don’t drown, with dolphins typically dozing for around 10 hours a day.
例如，海豚和鯨魚睡覺時會保持一半大腦清醒，所以它們不會淹死，海豚通常一天會睡10個小時左右。

The method is known as ‘logging’and it has been observed in bottlenose dolphins, which keep half of their brain a low level of alertness.
這種方法稱爲“運行記錄”，在寬吻海豚身上就能觀察到這一點，它們能使一半大腦保持較低的警覺性。

This allows the dolphin to retain enough consciousness to carry on breathing through its blowhole.
這使海豚能保留足夠的意識去通過噴水孔呼吸。

While sea otters aren’t alert while they sleep, they form rafts to they don’t drift away from each other.
然而海獺睡覺時並不警覺，他們彼此手牽手，這樣就不怕在睡夢中被海浪衝散了。

The creatures sometimes hold hands, or paws, when they sleep and typically eat, sleep and rest while floating in groups called rafts.
這種動物睡覺時有時手拉手，有時爪牽爪，通常成羣結對像竹筏一樣漂在水上吃、睡和休息。

These can range in numbers from a handful to hundreds of otters.
海獺的羣體數量從幾隻到幾百只不等。

Migrating birds can sleep while flying, with some drinking and napping during epic journeys that last for six months.
候鳥能邊飛邊睡，在持續六個月的遷徙過程中伴隨着飲水和小睡。

Scientists recently have found that migrating birds, such as the Alpine swift, can fly for 200 days without stopping.
科學家最近發現了高山雨燕等候鳥能夠在空中持續飛行200天。

The bird’s activity appeared to rise and fall during flight in a 2011 study, leading experts suggest that they control their wings while flying.
2011年的研究顯示這種鳥飛行期間忽高忽低，由此，專家表示它們飛行時能夠控制翅膀。