动物们如何进行伪装?(上)

Camouflage is the by-product of an evolutionary arms race between one group - the predators - that want to eat another group - the prey.

伪装是想要吃掉猎物的捕食者群体和猎物群体之间进化竞赛的副产品。

Prey seek to survive by tricking the perceptual and cognitive systems of the predators.

猎物通过欺骗捕食者的感知和认知系统得以生存。

And predators look to eat by breaking through the camouflage of the prey.

捕食者通过识破猎物的伪装来寻找食物。

To put it all more formally, predators need to maximise their perception of signal (their proposed meal) from the noise (the general environment); the goal of prey is to minimise that same signal-to-noise ratio.

更专业一点来说，捕食者需要将自己感知“信号”（他们可能的食物）的能力在噪音中（一般环境中）最大化；而猎物的目标是将相同的信噪比降至最低。

While the physical manifestations of camouflage might be diverse, they function in one of three ways: to impair detection, to impair identification or to redirect attack.

虽然伪装的物理表现可能多种多样，但它们的作用方式一般有三种：干扰捕食者的探测、干扰捕食者的识别，以及改变其攻击方向。

Methods that impair detection trick the perceptual system of a predator into believing that the prey is simply not there.

干扰捕食者的探测指欺骗捕食者的感知系统，让他们相信猎物根本不在那里。

Octopuses change colour to match their backgrounds, for example.

举例来说，章鱼会改变自己身体的颜色，使之与背景融为一体。

The tasselled wobbegong shark conceals its shadow against the ocean floor by being incredibly wide and flat.

叶须鲨的体型十分宽大而平坦，能够将自己隐藏在海底。

The white bellies of penguins match the sky, and their black coats, the depths of the ocean, in what is known as "countershading".

企鹅腹部的白色与天空的颜色相一致，背部的黑色皮毛与海洋深处的颜色相一致，这也就是我们所说的“反荫蔽”。

The arctic fox sports white fur in the winter and brown or grey in the summer.

北极狐的皮毛在冬天是白色，在夏天是棕色或灰色。

The comb jelly is transparent.

栉水母身体是透明的。

Deep-sea fish are very black.

深海鱼的颜色很黑。

Often, the evolution of this kind of camouflage is detectable on a shorter timescale too - the populations of dark-coloured peppered moths grew in England, for example, as sooty pollution increased in the 19th century during the Industrial Revolution.

通常来说，在较短一段时间内也能观察到伪装的进化发展——例如，19世纪工业革命期间，烟尘污染增加时，英国深色胡椒蛾的数量有所增加。

Correspondingly, the population of light-coloured moths rose when pollution levels fell.

相应地，当污染水平下降时，浅色蛾的数量会有所增加。

Impairing identification tricks the cognitive system of predators into thinking that whatever it is looking at is uninteresting (and definitely not food-like).

干扰捕食者的识别指引导捕食者的认知系统，使其认为自己目前正在观察的东西毫无趣味(而且肯定不像食物)。

The dead leaf butterfly, for example, looks like a dead leaf.

例如，枯叶蛱蝶看起来就像一片枯叶。

Predators themselves use this too - leopards have high-contrast disruptive patterning which allows them to better blend into shadowy bushes and tall grass to avoid detection by their prey.

捕食者自己也使用这种技巧——豹子身上有高对比度的破坏性花纹，这使得它们能够更好地融入幽暗的灌木丛和高高的草丛中，以免被猎物发现。

Redirecting attention is a way to try to reduce the lethality of attack, thereby increasing the chances of survival.

转移注意力是试图降低捕食者攻击强度，从而增加自身生存机会的技巧。

The eyespots on the wings of a peacock butterfly, for example, divert attention towards less important regions of the insect's body.

例如，孔雀蛱蝶翅膀上的眼点会让捕食者的注意力转移到它身体不太重要的区域。

Zebras' stripes deploy a technique called "motion dazzle", which disrupts a predator's ability to work out which direction the animals are moving in.

斑马的条纹利用了一种名为“运动性眩晕”的错觉，可以扰乱捕食者对其移动方向的判断。

How good are any of these camouflage tactics?

这些伪装战术有多有效？

A study published this week in Proceedings of the Royal Society B tries to find out.

本周发表在《英国皇家学会会刊B》上的一项研究试图找出答案。