双语揭秘信鸽的奥秘：鸽子脑内自带空间图

The mystery of how a pigeon can always find its way back home hasfinally been solved.

　　Scientists believe that pigeons have a spatial map that allowsthem to fly in an unfamiliar territory and know exactly where theyare going。

　　The finding replaces the current theory that pigeons comparethe coordinates of their location with those of the home loft andthen systematically reduce the difference between the two to findtheir way home。

　　This earlier theory likens the navigation of pigeons to thatof flying robots。

　　But experiments carried out at the University of Zurich haveshown that pigeons possess cognitive capabilities。

　　In unknown areas, the scientists claim pigeons recognise wherethey are in relation to their home loft and are able to choosetheir targets themselves。

　　Homing pigeons and migratory birds determine their flightdirection with the help of the Earth’s magnetic field, the starsand the position of the sun。

　　Nicole Blaser, a doctoral student in biology at the Universityof Zurich proposed the theory that pigeons have a spatialunderstanding and knowledge of their position in space relative totheir home loft。

　　This theory presupposes a type of mental map in their brainand thus cognitive capabilities. Up until now, there has not beenany clear evidence to support this。

　　For their experiments, Blaser and her colleagues fitted homingpigeons with miniature GPS loggers in order to monitor the birds’flight paths。

　　Beforehand the researchers trained the pigeons not to obtainfood in the home loft, as was normally the case otherwise。

　　‘We fed the pigeons in a second loft around thirty kilometresaway, from where they each had to fly back to their home loft’,said Blaser, explaining the structure of the experiment。

　　The scientists then brought the pigeons to a third placeunknown to the pigeons in completely unfamiliar territory。

　　This release site was in turn 30 kilometres from the home loftand the food loft. Natural obstacles obscured visual contactbetween the release site and the two lofts。

　　One group of the pigeons was allowed to eat before flyinghome. The other group was kept hungry before starting off。

　　‘We wanted to find out whether the hungry pigeons fly first tothe home loft and from there to the food loft or whether they areable to fly directly to the food loft,’ said Blaser。

　　‘As we expected, the satiated pigeons flew directly to thehome loft’, said professor Hans-Peter Lipp, neuroanatomist at theUniversity of Zurich。

　　‘They already started on course for their loft and onlydeviated from that course for a short time to maketopography-induced detours.’

　　The hungry pigeons behaved differently, setting off on coursefor the food loft from the very beginning and flying directly tothat target。

　　They also flew around topographical obstacles and thenimmediately adjusted again to their original course。

　　Based on this evidence, Blaser believes that pigeons candetermine their location and their direction of flight relative tothe target and can choose between several targets。

　　Blaser concluded that pigeons have a type of cognitivenavigational map in their heads and have cognitivecapabilities。

　　‘Pigeons use their heads to fly’, she said。

　　据英国《每日邮报》7月26日报道，瑞士苏黎世大学的科学家经过实验得出结论：鸽子大脑中有一幅空间地图，因而能够在陌生地区飞行，并能判断出确切的飞行方向。

　　现有理论认为，鸽子把自己所处的位置坐标与家里的鸽房坐标相比较，有条理地减小两者之间的区别，进而找到回家的路。以往的研究认为，信鸽和候鸟在地球磁场、星星和太阳位置的帮助下确定飞行方向。而苏黎世大学生物学博士尼科尔·布莱泽则提出新的理论：鸽子具有空间识别能力，知道自己相对于鸽房的空间位置。该理论预先假定鸽子的大脑中有一种意象图，因而具有认知能力。在此之前，没有任何显著证据支持这一理论。

　　在实验中，布莱泽和同事在信鸽身上安装了微型GPS记录器，以便监测其飞行路线。
与以前的实验不同，研究人员预先训练鸽子不在自己的鸽房内获取食物。“我们在大约30公里外的另一个鸽房喂鸽子，每只鸽子都必须从那里飞回自己的鸽房，”布莱泽解释说。接着，科学家把鸽子带到距离鸽房和喂食鸽房30公里外的陌生地点，让自然障碍物模糊了放飞地点与这两个鸽房之间的视觉接触。

　　一组鸽子获准在回家之前吃东西。另一组鸽子则在出发前保持饥饿。布莱泽说：“我们想弄清楚，饥饿的鸽子是先飞到自己的鸽房再从那里飞到喂食鸽房，还是可以直接飞到喂食鸽房。”

　　“正如我们所料，吃饱的鸽子直接飞回了鸽房，”苏黎世大学神经解剖学教授汉斯-彼得·利普说，“它们已经开始朝鸽房方向飞了，只是在地形诱导下，短时间偏离航线，绕了点路。”饥饿鸽子的行为则有所不同，它们从一开始就朝喂食鸽房的方向飞，直接飞向了目标。

　　据此，布莱泽认为鸽子可以确定自己的位置和相对于目标的飞行方向，而且能够在几个目标之间做出选择。她由此得出结论，鸽子的脑袋里有一种认知导航地图，也具有认识能力。