【经济学人】脑容量较小的鸟类容易发生交通事故丨2017.03.30丨总第856期

NATURAL selection is a harsh interrogator at the best of times. But if you are a bird, it has an extra question, not asked so forcefully of animals that cannot fly: “is that extra gram of weight really necessary?” Contrary to the insult “bird-brained”, birds are not notably more stupid than mammals, but the pressure to keep organs light applies to the cerebrum as much as it does to anything else.（读者试译句）

自然选择即使在最好情况下也表现得十分严苛。但如果你是一只鸟，与其他不能飞行的动物相比，你有一个额外的问题需要考虑即如何尽可能减少累赘。 （期待您的翻译，明天会有针对这句话的长难句解析哟~）

• Bird-brained：adj. 愚蠢的

• Mammals：n. 哺乳类；哺乳类动物

• Cerebrum：n. 大脑

For the past century, though, birds have faced a new enemy that might require them to get smarter: the motor car. These days, cars and other motorised vehicles kill around 250m birds a year. That sounds like a significant selective pressure, so Anders Moller, an evolutionary biologist at the University of Paris-Sud, in France, decided to find out whether it really was.

在上个世纪，鸟类遇到了一个新的敌人——汽车。这令它们需要变得聪明些，因为每年因汽车和其他机动车辆而丧命的鸟类数量约为2.5亿。选择压力听上去如此之大，这令法国巴黎南大学的进化生物学家Anders Moller决定一探究竟。

Dr Moller’s hypothesis was that avoiding vehicles needs intelligence, and intelligence needs a big brain. The conclusion of this syllogism is that small-brained birds are more likely to be road-kill than large-brained birds are. To test this idea, though, he needed data on a lot of dead birds.

Moller博士猜想，规避汽车需要一定的智力，而一定的智力则意味着大脑要足够大。这一系列推论的结果是，脑容量较小的鸟类比脑容量较大的鸟类更容易因车祸而丧命。为了测试这一观点，他需要大量的鸟类尸体数据。

• Hypothesis：n. 假设

• Syllogism：n. 三段论；推论

That serendipity plays a part in science is undeniable. Fleming’s chance observation of Penicillium mould on bacterial plates led to antibiotics . Kekulé’s dream of carbon atoms dancing in rings led to his model of the structure of benzene. Dr Moller’s serendipity was to meet, 30 years ago, a taxidermist called Johannes Erritzoe. Mr Erritzoe has, during his career, exhaustively recorded details of the specimens that have passed through his hands. These details include the weights of the internal organs, and likely cause of death, of 3,521 bird specimens of 251 species.

不可否认的是，机缘巧合也是科学的一部分。Fleming正是因为偶然间观察到琼脂上的青霉菌才发明出抗生素。Kekulé在梦中梦见碳原子围成环形，进而提出了苯环结构。而Moller的好运之处在于，他在研究期间获得了关于鸟类车祸事件的详尽记录资料，其中包括251种、共3521个鸟类样本的内部器官重量和可能的死亡原因。

• Serendipity：n. 意外发现珍奇事物的本领；有意外发现珍宝的运气

• Penicillium：n. 青霉菌；青霉菌属

• Mould：n. 模具；霉

• Bacterial：adj. 细菌的

• Antibiotics：n. 抗生素；抗生学

Since they met, Dr Moller and Mr Erritzoe have collaborated on many papers. This time, they asked whether there was a difference between the weights of the organs of birds killed by traffic and of those that had died of other causes. They found, as they report in Royal Society Open Science, that there was not—with a single exception. The smaller a bird’s brain, when controlled for its body size, the more likely it was to have been road-kill. Some 60% of the smallest-brained birds Mr Erritzoe handled had died this way. Among the largest-brained, death by traffic was unheard of.

Moller博士和Erritzoe先生自结识起便合作发表了许多论文。这一次他们的论题是：对于死于交通事故的鸟类和具有其他死因的鸟类，二者的器官重量是否存在差异。经过研究，他们在《Royal Society Open Science》中阐述了结论：此二者几乎没有差别，只有一项例外。鸟类由于需要控制身体尺寸而导致大脑较小，那么它们死于交通事故的概率也相应较高。根据Erritzoe先生手中的资料，大脑最小的鸟类中约60%都死于交通事故，而对于大脑最大的鸟类，则并没有死于交通事故的报告。

All this suggests a selective pressure on birds in parts of the world with lots of traffic to acquire bigger brains, even at the cost of the extra energy required to keep those brains airborne . It also leads to a prediction, in a field of science—evolutionary biology—that is rarely in a position to make them. This is that the average weight of bird brains may rise over coming decades. Whether anyone with Mr Erritzoe’s enthusiasm for data collection will provide the means to test that prediction is, though, a different question.

以上信息说明，全球鸟类的一项选择压力在于，由于交通日渐繁忙，为避免死于交通事故，需要消耗额外能量来保持更大的大脑。据此也延伸出一种预测，即鸟类大脑的平均重量将在今后几十年内增大。这种预测在进化生物学领域是非常罕见的。不过，是否有人怀有与Erritzoe先生同等的热情，愿意收集数据并提供关于该预测的测试方法，这就是另一回事了。

• Airborne：adj. 空运的；空气传播的；风媒的

• Enthusiasm：n. 热心，热忱，热情

翻译 ▍ 陌生、c、西柚

审核 ▍ 妖精

编辑 ▍喵喵