Sloths:The World'sSlowest Mammals 樹懶：世界上最慢的哺乳動物

Juno

每年的10月20日是一個有趣的日子——國際樹懶日。樹懶是樹棲動物，它們動作遲緩，常用爪倒掛在樹枝上數小時不移動。樹懶的移動速度是甫乳動物中最慢的，比我們所知的烏龜還要慢，它們甚至懶得去吃，懶得去玩?！覀儾灰獞械萌チ私膺@種可愛的動物哦！

Sloths are tree-dwelling mammals that mainly live in the rainforests of South andCentral America. With their long arms and 1）shaggy fur， they 2）resemble monkeys， butthey are actually related to armadillos and anteaters. They can be 0.6 to 0.8 meterslong and， depending on species， weigh from 3.6 to 7.7 kilograms.

With long， curved claws， sloths can hang upside down with little or no effort.Sloths spend most of their lives in the trees， where they hang upside-down frombranches and 3）vines. Sloths eat， sleep. mate and even give birth while hangingaround in the trees！

Sloths eat leaves， fruit and some select fresh green 4）shoots. Though mostlyherbivorous， they may occasionally snack on a 5）arval insect. They 6）lap dew dropsoff of leaves and fruits， and get additional water from their food. Sloths have the lowest7）metabolic rate of any mammal， which means that it takes them a long time to digestanything. So long， in fact， that a sloth usually only climbsdown from its tree about once a week to poop！

True to their name， sloths sleep for about 15 hours a day. They're mostly8）nocturnal， sleeping during the daytime and waking up at night to eat. Sloths moveextremely slowly， only managing to cover about 6–8 feet （1.8–2.4 meters） per minute.As a comparison， walking at your normal speed you'd probably be moving at about 84meters per minute. So even when walking you're about 39 times faster than a sloth！But sloths are surprisingly good swimmers. They can swim through water three timesfaster than they can move on the ground！

樹懶主要分布在南美洲和中美洲的熱帶雨林中，是一種樹棲哺乳動物。樹懶有著長長的手臂和蓬松的毛發(fā)，很像猴子，但實際上它們與犰狳和食蟻獸有近親關系。它們可以長到0.6～0.8米，根據亞種的不同，重量可達3.6～7.7千克。

由于樹懶長而彎曲的爪子，它可以毫不費力地倒掛在樹上。樹懶一生的大部分時間都在樹上度過，它們在樹枝和藤蔓上倒掛著。樹懶在進行吃、睡、交配等活動時都懸掛在樹上，甚至連生產時也是掛在樹上！

樹懶吃樹葉、水果和一些精選的新鮮嫩芽。雖然它們大多是草食性的動物，但偶爾也會吃一些幼蟲昆蟲。它們舔食樹葉和水果上的露珠，并從食物中獲得額外的水分。樹懶的新陳代謝率是哺乳動物中最低的，這意味著它們需要很長時間來消化任何東西。消化時間太長了，事實上，樹懶通常每周只從樹上爬下來一次拉便便！

樹懶的懶惰名副其實，每天睡15個小時左右。它們大多在夜間活動，白天睡覺，晚上醒來吃飯。樹懶移動極慢，每分鐘只能爬6～8英尺（1.8～2.4米）。你可以比較一下，以你的正常速度行走，大約為每分鐘84米的速度。所以，即使走路，你也比樹懶快39倍！但出人意料的是，樹懶擅長游泳。它們在水中游泳的速度是在地面上移動速度的三倍！