Warm Climates Support Longer Limbs

Animals that live in cold climates tend to have stubby limbs—shorter arms and legs—even smaller ears and tails. Picture a penguin and you’ll see what I mean. Biologists have long assumed that these stumpy appendages are an evolutionary adaptation. Shorter extremities minimize heat loss, so animals that are more compact are better suited to the cold.But scientists from Ohio say that temperature may have a more direct effect on the length of an animal’s limbs. Because they find that turning up the heat helps cartilage grow—results that were published in the Proceedings of the National Academy of Sciences.The researchers raised mice at several different temperatures, and they confirmed that those kept at a balmy 80 degrees were longer limbed than those who lived at a more chill 45. But how does a little heat make mice more leggy? The answer, they find, lies in the cartilage. Long bones grow from the cartilage found at either end. And the warmer it is, the more that cartilage grows, even when it’s just sitting in a test tube. Which I guess means it’s possible that the dog days of summer lead to longer-legged dogs.

Words

stubby：断株一般的，短而粗硬的，粗而短的。stub：残端，残段，残牙，残肢，烟蒂

stumpy：多残株的，粗短的，矮胖的。stump：树桩，烟头，残余

appendage：[əˈpendɪdʒ].附加物，附属肢体

extremity：前端，末端，四肢，手脚，极端，困境，极点

compact：使紧密，使简洁，压紧，结实地组成，订立契约

turn up：出现，发生，开大

cartilage：[ˈkɑ:tɪlɪdʒ].软骨

软骨：人类骨骼中一种致密的结缔组织。软骨由深埋在坚实的凝胶状基质中的致密胶原纤维网所组成，不含血管。软骨可分三种：①透明软骨分布最广，组成胚胎的骨架，并持续存在于成人活动关节的骨端、肋骨末端及鼻、喉、气管、支气管中。②纤维软骨构成椎间盘的纤维环，极为坚韧。③弹性软骨中除胶原纤维外还含有弹性纤维，因此最为柔韧；人类的外耳即由弹性软骨构成。在胚胎期，人的大部分骨骼由软骨构成，以后才被骨取代（大英百科）。

balmy：

温和的，柔和的，芬芳的，芳香的，宜人的。balm：香油，安慰物，香膏

leggy：长腿的，茎长的，腿细长的

test tube：试管

dog days：大热天，不利时期，三伏天，淡季

古罗马人把the Dog Star（天狼星,又称Sirius）与太阳一起出没的期间，即自七月三日起至八月十一日止的四十天称为 dog days。他们相信这期间由于太阳的热度加上光度极强的天狼星的热度会形成酷暑。