从进化角度来看,"喵星人"比"汪星人"更好

It's the debate that has long divided animAl lovers. Now scientists have confirmed that cats really are better than dogs – at least from an evolutionary perspective.

一直以来，"猫和狗哪个更好"这一问题将动物爱好者划分为两大阵营。现在科学家已经证实猫确实比狗更好——至少从进化的角度来看是这样。

A groundbreaking study of 2,000 ancient fossils reveals that felids – the cat family – have historically been much better at surviving than the "canid" dog clan, and often at the latter’s expense.

一项对2000个古代化石进行的开拓性研究揭示了从历史上看，猫科动物家族的生存能力远远强于犬科动物家族，而且猫科动物的生存是以犬科动物的损耗为代价的。

The research finds that cats have played a significant role in making 40 dog species extinct, outcompeting them for scarce food supplies because they are generally more effective hunters. But researchers found no evidence that dogs have wiped out a single cat species.

这项研究发现，猫科动物在40个犬科物种的灭绝过程中发挥了重要作用。由于猫科动物通常是更有效率的捕猎者，在夺取供应不足的食物的竞争中猫科动物胜过了犬科动物。但是研究人员没有发现任何犬类动物消灭掉一个猫科物种的证据。

The dog family – which includes the wolves from which today’s domesticated dogs are descended – originated in North America about 40 million years ago and reached a maximum diversity around 20 million years later, when there were more than 30 species on the continent. At that point, the cat family arrived from Asia.

犬科家族——包括现在的驯养狗的祖先狼——起源于约4000万年前的北美洲，在大约2000万年后达到了物种多样性的巅峰，当时在北美洲有超过30个犬类物种。与此同时，猫科动物也从亚洲来到此地。

"The arrival of cats to North America had a deadly impact on the diversity of the dog family. We usually expect changes in climate to play the overwhelming role in the evolution of species. Instead, competition among different carnivore species proved to be even more important for the dogs," said the report’s lead author, Dr Daniele Silvestro, of the University of Lausanne in Switzerland.

这项研究报告的第一作者、瑞士洛桑大学的达妮埃尔·西尔韦斯特罗博士表示："猫科动物的到来给犬科动物的物种多样性造成致命打击。我们通常预计气候变化会在物种进化过程中发挥最重要的作用。但对于犬科动物来说，不同食肉动物物种间的竞争被证明是更重要的。"

The influx of cats prompted a period of dramatic decline among the dog clan. This has left North America with just nine species of wild dog today, comprising different variations of wolves and foxes, according to the fossil analysis published in the journal PNAS.

猫科动物的涌入导致犬科动物数量在一段时间内大幅下降。依据这项发表在美国国家科学院院刊（PNAS）上的化石分析，这造成了如今北美洲仅存九个犬类物种，包括狼和狐狸的不同变种。

Dr Silvestro says it is unclear exactly why, when times were tough, the cats were able to see off dogs so comprehensively. But he believed it could be something to do with the retractable claws that ancient cats have passed down to their domesticated descendants, but which dogs don’t have.

西尔韦斯特罗博士称，目前还不是十分清楚在当时的艰难岁月，猫科动物为什么能将犬科动物"驱逐"得那么彻底。但是他认为这可能跟古代猫科动物伸缩自如的爪子有关，这是犬科动物所不具有的。古代猫科动物还将这种爪子遗传给了自己的后裔家猫。

Millions of years ago, some dog species, such as wolves, were effective killing machines, chasing down their prey at high speed and devouring it. All surviving dog species fall into this "runner" camp.

数百万年前，某些犬科物种（比如说狼）是有效的杀戮机器，能以高速追捕猎物并吞食掉。所有幸存的犬科动物都属于"奔跑系猎手"阵营。

But other dog species ambushed their prey in a manner similar to the cat family. However, these dogs weren’t as good as the cats at this technique – and all the canid species who used it are now extinct.

不过也有其他犬科动物伏击猎物的方式与猫科动物相似。然而，这些犬类动物并不像猫科动物那样擅长这项技能——所有曾使用这项技能的犬科动物现在都已经灭绝了。

Dr Silvestro explained: "The cats have retractable claws which they only pull out when they catch their prey. This means they don’t wear them out and they can keep them sharp. But the dogs can't do this, so they are at a disadvantage to the cats in an ambush situation."

西尔韦斯特罗博士解释称："猫科动物只有在抓到猎物时才会亮出它们可伸缩的爪子，这意味着它们不会磨损并能够时刻保持锋利，但是犬科动物不能做到这一点。因此，同猫科动物相比，它们在伏击方面处于劣势。"

The evolutionary success of carnivorous animals is strongly linked to their ability to obtain food, meaning that there can be significant competition for prey when there is insufficient supply for the population.

食肉动物的进化成功在很大程度上与它们获取食物的能力有关，这也意味着当食肉动物的食物供应不足时，猎物的争夺将十分激烈。

"Felids must have been more efficient predators than most of the extinct species in the dog family," the report concluded.

该报告总结称："猫科动物与那些灭绝了的犬科动物相比一定是更有效的捕食者。"