十万个为什么·科学阅读30篇（4）

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为什么某些沙漠蚂蚁利用偏振光模式导航？

Desert ants like Cataglyphis walk vast distances across featureless sand without landmarks or scent trails.
They possess specialized ommatidia in their compound eyes that detect the angle of polarized light in the sky.
Sunlight scatters in Earth’s atmosphere and creates invisible polarization bands radiating from the sun’s position.
Even under cloudy skies, these patterns remain detectable thanks to ultraviolet-sensitive photoreceptors.
The ant’s brain integrates this data with step-counting and celestial cues to compute a direct return path.
This 'celestial compass' allows pinpoint navigation within one meter after traveling over 100 meters.
Unlike bees, these ants do not rely on memory of terrain but on real-time optical computation.
Researchers confirmed this by rotating polarization filters above foraging ants and observing disorientation.
Their neural circuitry processes polarization angles faster than human-made optical sensors can measure.
This ability evolved as a survival tool where visual landmarks vanish within seconds in shifting dunes.