When desert locusts are well fed, they're solitary creatures.
当沙漠蝗虫有足够的食物时，它们是独居的生物。
But when food becomes scarce,
但是在食物短缺时，
hungry, desperate locusts crowd onto small patches of land where they can still find something to eat.
饥饿的蝗虫逼于无奈群拥到一小块仍然还有食物的土地上。
Contact between different locusts' hind legs set off a slew of reactions that change their appearance and behavior.
当不同蝗虫的后腿相触时，一连串的反应将发生并改变蝗虫的外观和行为。
Now, instead of shunning their peers, they seek each other out.
现在，蝗虫不再避开同类，而会开始寻找同伴。
The locusts eventually start marching and then fly away in large numbers seeking a better habitat.
这些蝗虫大规模地成群飞行，去寻找更好的栖息地。
These gigantic swarms can host millions of insects and travel thousands of miles, devastating vegetation and crops.
这些巨大蝗群的蝗虫数量可达几百万只，飞行距离长至几千英里，在途中破坏无数植物和庄稼。
They stay close to each other, but not too close, or they might get eaten by their hungry neighbors.
它们彼此靠近着飞行，但不会过于紧密，否则会被饥饿的同伴吞噬。
When many individual organisms, like locusts, bacteria, anchovies, or bats,
但大量的同类生物，如蝗虫，细菌，鳀鱼或蝙蝠，
come together and move as one coordinated entity, that's a swarm.
聚集起来，以一个单体协调地运动时，就形成了“群”。
From a handful of birds to billions of insects, swarms can be almost any size.
从寥寥无几的飞鸟到数以亿计的昆虫，群的大小不拘。
But what they have in common is that there's no leader.
这些群都有一个共同点，就是没有领导。
Members of the swarm interact only with their nearest neighbors or through indirect cues.
群的成员只跟离它们最近的同类互动，或通过间接信号沟通。
Each individual follows simple rules: Travel in the same direction as those around you, stay close, and avoid collisions.
每个成员都遵守一些简单的规则：跟身边的成员往同样的方向移动、互相挨近和避免碰撞。
There are many benefits to traveling in a group like this.
像这样成群结队地移动有很多好处。
Small prey may fool predators by assembling into a swarm that looks like a much bigger organism.
体型小的猎物形成看似巨大的生物群队，借此蒙骗它们的天敌。
And congregating in a large group reduces the chance that any single individual will be captured.
聚集成群也能减少个别生物被捕猎的机会。
Moving in the same direction as your neighbors saves energy by sharing the effort of fighting wind or water resistance.
和同伴往同一个方向移动可以一起抵抗风或水的阻力，从而节省体力。
It may even be easier to find a mate in a swarm.
在群队里也能更容易地找到配偶。

Swarming can also allow groups of animals to accomplish tasks they couldn't do individually.
成群结队也能帮动物完成它们无法单独完成的任务。
When hundreds or millions or organisms follow the same simple rules,
当成千上万的生物都同时遵守同样的简单规则时，
sophisticated behavior called swarm intelligence may arise.
称为群体智能的复杂行为就会出现。
A single ant can't do much on its own,
一只蚂蚁无法独自完成很多事，
but an ant colony can solve complex problems, like building a nest and finding the shortest path to a food source.
但是一群蚂蚁却能解决复杂的问题，比如筑巢和找到离食物最近的路线。
But sometimes, things can go wrong.
但是有时候会有差错。
In a crowd, diseases spread more easily, and some swarming organisms may start eating each other if food is scarce.
疾病更容易在群体中散播，一些群居的生物更会在食物短缺时自相残杀。
Even some of the benefits of swarms, like more efficient navigation, can have catastrophic consequences.
甚至一些成群结队的好处，比如提高导航的效率，也可以有灾难性的后果。
Army ants are one example. They lay down chemicals called pheromones which signal their neighbors to follow the trail.
行军蚁就是一个例子。它们会释放出一种叫信息素的化学物质，指示邻近的同类跟从它们的踪迹。
This is good if the head of the group is marching towards a food source.
如果前面的蚁在步向食物，这非常有用。
But occasionally the ants in the front can veer off course.
但有时候，前面的蚂蚁偏离了正途。
The whole swarm can get caught in a loop following the pheromone trail until they die of exhaustion.
整个蚁群可能跟着信息素绕圈而行，直到力竭身亡。
Humans are notoriously individualistic, though social, animals.
人类是出了名奉行个人主义但却群居的生物。
But is there anything we can learn from collective swarm-based organization?
我们可以从群体性组织学习到什么吗？
When it comes to technology, the answer is definitely yes.
在科技领域，答案是肯定的。
Bats can teach drones how to navigate confined spaces without colliding, fish can help design software for safer driving,
蝙蝠可以教导无人驾驶飞机怎样在密封的空间里畅行，鱼可以帮助人类设计安全驾驶的软件，
and insects are inspiring robot teams that can assist search and rescue missions.
而昆虫能够启发机器人协助搜救任务。
For swarms of humans, it's perhaps more complicated and depends on the motives and leadership.
人类的成群结队也许比较棘手，而且成败取决于动机和领导能力。
Swarm behavior in human populations can sometimes manifest as a destructive mob.
人类的群体行为有时候会在极具破坏力的暴民身上体现。
But collective action can also produce a crowd-sourced scientific breakthrough an artistic expression, or a peaceful global revolution.
但群体行动也可推动众包的科学突破、艺术表现，或和平的全球革命。