蚂蚁为什么总能找到回家的路？

　　Next time you need directions, maybe ask an ant. Because these clever little critters are such masters of navigation that some can find their way home… whether they’re walking forward, backward, or sideways. That’s according to a study in the journal Current Biology.

　　下次，当你需要辨别方向时，也许可以问问小蚂蚁。因为这些聪明的小东西真是擅长导航——无论是向前向后或者走小路，有些蚂蚁总能找到回家的路呢。该研究结果发表在《当代生物学》杂志。

　　Ants often travel long distances—well, for them—when they’re searching for food to bring back to their nests. And their built-in GPS appears to function just fine even when they wind up having to travel in reverse because they’re dragging a huge morsel. But how do these backward bugs know where they’re going?

　　蚂蚁通常会出行很远的距离——好吧，对它们来讲算是很远了——当它们外出寻找食物回家的时候。它们身体里内置的定位系统即使在它们因为拉着一个巨大的食物碎屑而不得不结束旅行掉头回家的时候也能正常发挥功能。但是这些向后掉头的小东西是如何知道它们要去的方向呢?

　　To find out, researchers went to Spain to mess with some desert ants. They found an active nest and surrounded it with barriers that forced the foraging ants to follow a particular path back home. Once the ants were familiar with the maze, the researchers would scoop them up…hand them a cookie crumb…and then put them back in a different location…one that required taking a 90 degree turn to get to the nest.

　　为了找寻答案，研究人员们去西班牙骚扰了一下某些沙漠地带的蚂蚁。结果他们发现，一个有活力的巢穴以及围绕着巢穴的一些屏障会迫使这些觅食的蚂蚁循着一条特殊的路径返家。一旦这些蚂蚁熟悉了这种迷宫式的路线， 研究人员们就会把它们拿起来，给它们一块饼干碎屑，然后把它们再放到另一个不同的位置，这里需要调转90度角的方向才能返回巢穴。

　　What the researchers saw was that the ants that were carting a small, easy-to-carry crumb would dash forward with confidence and were able to hook a right and head on home. Presumably because they could see where they were going and recognized the route.

　　研究人员们发现，这些蚂蚁会抓着小块的容易携带的食物碎屑向前猛冲，并能找到正确的回家方向。或许因为它们能识别它们要去的地方的位置和路线。

　　But some of their nest-mates were given a cookie crumb so large that they had to travel aft-first, pulling their prize behind them. These ants would set off in the correct general direction. But those that stuck with going in reverse would miss the turnoff to the nest.

　　可是有些同伴负责运送大一些的食物碎屑，它们就不得不跟着前面的走，后面拽着食物。这些蚂蚁可以行驶在正确的方向上，可是那些跟在它们后面的向原来行驶方向走的蚂蚁们就不能掉头回家。

　　Some of the rearward ants, however, stopped to get their bearings. They would drop the cookie and turn around to take a look at the landscape. This quick peek allowed the six-legged savants to reset their inner maps. So that after turning back around to grab their cookies they headed in the right direction, even going back-end first.

　　某些在后面的蚂蚁，会停下去搜索方向。它们会扔下食物，向四周察看一下。这种快速察看可以使这些六条腿的小工们重新设置它们已知的地图。然后它们转回去拿起食物再朝着正确的回家路线行进，甚至能追上前面的同伴。

　　The ants-in-reverse appear to use celestial cues…like the position of the sun…to keep them on the straight and narrow. When the researchers used a mirror to make it look like the sun was on the other side of the sky, the beleaguered backward ants would turn tail for the opposite direction.

　　这些反转的蚂蚁貌似参考了天空上的物质定位，比如太阳的位置，使它们保持走一条细直线。但研究人员用一面镜子模拟太阳放在天上的另外一个位置时，这些向后走的受到方向困扰的蚂蚁，会调头朝向相反的方向走了。

　　So ants integrate a lot of information…about local landmarks, the position of the sun, and where their bodies are situated in space…to successfully bring home the bacon… all while going backwards.

　　所以蚂蚁是整合了许多信息的，比如位置地标、太阳的方位，还有它们自己的身体在天地间的位置，然后才能成功把肉带上，全部调头回家。

　　Lead author Antoine Wystrach, a CNRS researcher at the University of Toulouse 3, adds:

　　该文章的第一作者Antoine Wystrach，是在图卢兹第三大学的一位法国科研中心的研究人员，他补充道：

　　“This behavior is interesting in itself, as it implies a synergy between at least three types of memory: the long-term memories of the route sceneries, the memory of the new direction to follow, and the memory of the cookie left behind.”

　　这个行为本身很有趣，因为它暗示了在至少有三种类型的记忆之间的协同现象，路线周边的长期记忆，跟随的向新方向走的记忆，还有后面带着食物的记忆 。