While the weather outside may indeed get frightful in winter， a parka， knit hat， wool socks， insulated boots and maybe a roaring fire make things bearable for people who live in cold climates. But what about all the wildlife out there？ Won’t they be freezing？

冬天，室外的天气也许实在恶劣，但一件派克大衣、一顶针织帽、一双羊毛袜、一对保暖靴，或许再加上一堆熊熊燃烧的火焰，就能让生活在寒冷地区的人们将就过活。那外头的野生动物呢？它们不会冻僵吗？

Anyone who’s walked their dog when temperatures are frigid knows that canines will shiver and favor1 a cold paw—which partly explains the boom in the pet clothing industry. But chipmunks2 and cardinals don’t get fashionable coats or booties.

在寒冷天气遛过狗的人都知道，狗狗会冷得瑟瑟发抖，缩起冻僵的爪子——这在一定程度上解释了宠物服装产业繁荣的原因。不过，花栗鼠和北美红雀可没有时髦的外套或小靴子。

In fact， wildlife can succumb to frostbite and hypothermia3， just like people and pets. In the northern United States， the unfurred tails of opossums are a common casualty of cold exposure. Every so often an unusual cold snap in Florida results in iguanas falling from trees and manatees dying from cold stress.

事实上，同人类与宠物一样，野生动物也会遭受冻伤和体温过低的威胁。在美国北部，负鼠光秃秃的尾巴常因暴露在寒冷天气中而冻伤。佛罗里达遭遇罕见寒潮时，鬣鳞蜥会从树上跌落，海牛也会因冷应激而丧命。

Avoiding the cold is important for preserving life or limb （or， in the opossum’s case， tail） and the opportunity to reproduce. These biological imperatives mean that wildlife must be able to feel cold， in order to try to avoid the damaging effects of its extremes. Animal species have their own equivalent to what human beings experience as that unpleasant biting mixed with pins-and-needles sensation that urges us to warm up soon or suffer the consequences. In fact， the nervous system mechanisms for sensing a range of temperatures are pretty much the same among all vertebrates4.

为了保住生命或肢体（抑或是负鼠的尾巴），以及争取繁衍的机会，避寒至关重要。这些生物性需求，意味着野生动物必须能感知寒冷，才能尽量避免极端低温带来的破坏性后果。人类能感受到寒冷带来的刺痛与针扎交织的不适感，这种感觉促使我们尽快取暖，否则就要遭殃；动物也有类似的本能反应。事实上，所有脊椎动物感知温度范围的神经系统机制是基本相同的。

One winter challenge for warm-blooded animals， or endotherms5， as they’re scientifically known， is to maintain their internal body temperature in cold conditions. Interestingly though， temperature-sensing thresholds can vary depending on physiology. For instance， a cold-blooded—that is， ectothermic6—frog will sense cold starting at a lower temperature compared to a mouse. Recent research shows that hibernating mammals， like the thirteen-lined ground squirrel， don’t sense the cold until lower temperatures than endotherms that don’t hibernate.

对于温血动物（学名为恒温动物）来说，冬季的一大难题是在寒冷环境中维持体内温度。不过，有趣的是，感知温度的阈值会因生理差异而不同。例如，比起老鼠，冷血动物（即变温动物）中的青蛙在更低的温度下才会感觉到寒冷。最新研究表明，与不冬眠的恒温动物相比，冬眠哺乳动物（如十三条纹地松鼠）在更低的温度下才会察觉到寒冷。

So animals know when it’s cold， just at varying temperatures. When the mercury7 plummets8， are wildlife suffering or just going with the icy flow？

因此，动物们能感知到寒冷，只是产生这种感知的起点温度不同。