生活中的小谜团，你解开了吗？

为何猫会发出呼噜声?

We’ve shown before that cats don’t always purr when they’re happy, but the mystery goes way deeper than that. There is no purring organ in the throat of a cat, and even though extensive research has been done on the function itself, the exact origin of the function in the anatomy of cats is still unknown.It’s theorized that they might do it by the constriction and dilation of the larynx, but no evidence has ever been provided to prove or disprove that theory. It was, however, found that the frequency of a cat’s purr falls somewhere in the range required to accelerate bone regeneration and healing, so it might just be a healing superpower that we had no idea even existed in the animal kingdom. That might also explain why we take it to be a happy sound, as the frequency is not just beneficial for the cat—it tends to make us happier as well.

事实证明，当猫心情愉悦时并不一定会发出呼噜声，但问题远远不止如此简单。在猫的喉咙里并没有发出呼噜声的器官，即使在发声功能上做了详细的研究调查，确切的发声器官在猫身体的哪个部位仍无从得知。从理论上来说，声音与喉咙结构和扩张有关，但并没有任何理论证据来证实这一说法。但有研究指出，猫发出呼噜声的频率可达到加快骨头再生或治愈所需的范围。因此，这一举动亦可解释为一种不被人所知的治愈魔力。这也解释了为何人们认为猫发出的呼噜声是一种开心的声音：这个频率不但对猫有好处，亦令人类感到心情愉悦。

What Causes Hypnic Jerks?

为什么会有入睡抽动?

Often when we are about to fall asleep, we experience a kind of a falling sensation which causes us to wake up with a start. It happens to almost everybody, and the sensation is known as a hypnic jerk. It also sometimes happens when you tilt the chair you’re sitting on too far—somehow you can sense when you’re about to fall, and you wake up with a hypnic jerk. We really have no idea what causes them or whether they serve any modern purpose.

当我们将要进入睡眠状态时，常遇到一种要下坠的感觉，令我们突然惊醒。几乎每个人都有过这种经历，这就是我们所知道的“入睡抽动”。同样的感觉亦会发生在当你坐得离椅子太远，椅子倾斜而你感觉到快要从椅子上掉下去时，便会因为入睡抽动而突然惊醒。我们仍对造成入睡抽动的原因毫无头绪，亦不知其是否具有特定作用。

Why Do Giraffes Have Long Necks?

为何长颈鹿的脖子那么长?

Many may believe that only giraffes with long necks survived evolution because they had an advantage over the other, short-necked ones, but that’s not really true. Longer necks provide no particular advantage to giraffes because they care more about the type of leaf than the height at which it’s situated. If it’s confusing to you, science doesn’t have much of a clue either. There’s just no consensus on the exact conditions that would have caused long necks to be selected positively among giraffes.

大多数人相信长颈鹿的长脖子是演变的结果，认为长脖子比短脖子的长颈鹿在生存上更有优势，但事实并非如此。长脖子并不具有明显的优势，长颈鹿在进食时更关注的是树叶的种类而不是树叶所在的高度。若然你对此持怀疑态度，科学亦无法对此做出解释，科学界亦并没有对长脖子是优胜劣汰的结果这一结论达成共识。